Microbiology with Diseases by Taxonomy Chapter 26 Answers

Microbiology with Diseases by Taxonomy Chapter 26 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 26 Answers 1CM
The action of microbes does not only result in the spoilage of foods but would also be used in the improvisation of the shelf life of the food. The method of improvisation is obtained through the process of fermentation. The nutritive value of the food would also be improved in the process .
microbiology-with-diseases-by-taxonomy-chapter-26-answers-1cm

Microbiology with Diseases by Taxonomy Chapter 26 Answers 1CT
Recombinant DNA (Deoxyribonucleic acid) technology could alter the basic blue print of the plant DNA, which when altered in the right way could elaborately add significant value to the food produced. For example, as it is in the case of Bt cotton, the plant itself could be reengineered to ensure that it produces the toxin, thus enabling the wastage of money through the usage of commercial pesticides. This is one of the value additions to a plant as a result of recombinant DNA technology, which would also have a telling effect on the profit ratio as well.
It should be noted that thought the reengineered plants would affect the food value to the products. But the fact remains clear that the altered food grains might induce some unexpected outcomes that might arise at times, which act against both productivity and value. The altered gene will not be subjected to all the extremities that the plant is supposed to undergo mutation. As a result, there will definitely be some unanswered questions about their behavioral pattern, which is the reason why some people go against the production of transgenic crops.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 1FB
The nutrient value of the food pulls more microbes towards the food rather than processing and handling factors. This is because processing and handling factors, which are extrinsic factors. Moreover, higher the nutrient value, higher will be the concentration of microbes contaminating.
Thus, Intrinsic factors affecting food spoilage are properties of the food rather than processing or handling.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 1L
Carbon cycle initiates through the primary producers by fixing the inorganic carbon dioxide in their system as carbohydrates. The produced carbohydrates pass through the cycle and they are used by consumers. This would ultimately reach the inorganic form. The carbon cycle is a highly essential one, since the fixed carbon in the form of carbohydrate forms the major source of energy for the living system.
microbiology-with-diseases-by-taxonomy-chapter-26-answers-1l

Microbiology with Diseases by Taxonomy Chapter 26 Answers 1M
Fecal contaminations in water sources are often analyzed by the presence of coliforms in the sample. The coliforms are an integral part of the digestive system of humans and escapes to environment, through feces. However, it could be ascertained that fecal contamination could be matched only with Coliforms.
Thus, the statement, “organisms in water indicate contamination from feces, matches with the term, “coliforms.”
Hence, the correct option is C. Coliforms.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 1MC

  • Fermentation would enable a partial digestion of the foods thereby leading to a reduced acidity level. Though this would lead to a reduction in the quantum of pathogenic microorganisms, it would not completely eliminate the entire microbial content from the food. Hence, the correct option is (c) sterilize foods.
  • Fermentation of food provides a characteristic taste because of the production of certain chemicals as a result of microbial metabolism. Hence, the option (a) is incorrect.
  • Fermentation lowers the acidity of the food stuff thereby aiding in the reduction the spoilage of food stuffs. Hence, the option (b) is incorrect.
  • With a reduction in acidity and with the addition of salt and sugar during fermentation of certain food stuffs, the water activity level required for the unexpected microbe to survive would be reduced drastically. This would ultimately increase the shelf life of the product formed. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 1MTF
The given statement is false.
Fermentation of dairy products relies on lactic acid fermentation process and not on mixed acid fermentation. Mixed acid fermentation is an anaerobic fermentation process that results in the production of complex mixture of acids like acetate, lactate, formate, succinate, and ethanol. These acids are not produced in fermentation of dairy products.
Hence, the correct statement is “Fermentation of dairy products relies on lactic acid fermentation.”

Microbiology with Diseases by Taxonomy Chapter 26 Answers 2CT
A microbial growth could clearly be divided into a lag phase, log phase, stationary phase and a death phase. The lag phase is the time taken by the microbes when they are introduced into a new system. This is mainly to produce the enzymes and other growth factors necessary for the multiplication of the microbes. The log phase is where the microbes start multiplying exponentially. The next stage is the stationary phase where the number of new cells formed would be equivalent to the cells that dies. The last stage is the death phase, which would happen in a batch culture as a result of depletion of nutrients.
It is at the log phase that the microbes start synthesizing the primary metabolites. This is the reason why the production of primary metabolites is higher on compared to the secondary metabolites. It is during this phase, the metabolic activity of the microbial cell would be at their peak. The secondary metabolites on the other hand would be synthesized during the stationary phase where the metabolic activities of the cells have reduced. This is the major reason why primary metabolites are always higher in their proportion on compared with the secondary metabolites.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 2FB
Most of the microbes are capable of growing and multiplying at room temperatures than at either very high or very low temperatures. The food gets spoiled, depending on the type of food. Moreover, increases the chances of the food to be spoiled when it is left at room temperature. For example, bread consists of carbohydrates its spoilage does not produce much odor, but promote the growth of fungi – molds. Additionally, if the food contains proteins or fats, spoiled food produce terrible odors, due to the breakdown of proteins into short-chained fatty acids.
Thus, leaving foods out at room temperature increases the likelihood of food spoilage.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 2M
The toxin Bt is produced by an organism Bacillus thuringeinsis. The toxin when sprayed on the plants is further fed by specific groups of insects. This would lead to damage the guts of the insects, ultimately killing them. Thus, it could be ascertained that compounds that are capable of killing an insect could only be matched against Bt toxin.
Therefore, the statement, “compound produced by a bacterium that kills insects” matches with the term, “Bt toxin.”
Hence, the correct option is F. Bt toxin.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 2MC

  • Since, the quantum of alcohol produced and the product formed will be different every time with naturally occurring microbes are used. The use of natural bacterial culture is neglected. Hence, the option (a) is incorrect.
  • Though yeast is used in the fermentation process, those occurring naturally on the surface of the grapes cannot be used for fermentation. This is because the quantum of microbial inoculum cannot be the same in all process including natural yeasts. Hence, the option (b) is incorrect.
  • Fermentation is a process during which the sugars present would be converted into alcohol, as a result of fungal enzymatic process. Yeast is said to be involved in the production of enzyme in the conversion process. Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 2MTF
The given statement is False.
Sauerkraut involves the fermentation of salted cabbage. This involves the action of lactic acid bacteria. Though the process of sauerkraut production is fermentation, the process ends up not with the production of ethanol, but with the lactic acid.
Hence, the correct statement is “Sauerkraut production involves the lactic acid fermentation of cabbage.”

Microbiology with Diseases by Taxonomy Chapter 26 Answers 3CT
Ethanol, methane, and hydrogen could be used as an alternative fuel that could quench the needs of the present day. Ethanol could be produced through fermentation of molasses, which when mixed with petrol could be used as an alternative for gasoline. This is one of the ways, in which, we can reduce the usage of fossil fuels. But the production cost of ethanol is high and hence, it could be a hindrance for the consumers.
Methane is another gas that could be an effective alternative fuel. Methane could be combusted producing heat energy. But the limiting factor is that methane on combustion produces carbon dioxide and water. Since carbon dioxide is a greenhouse gas, the usage of methane gas is highly limited.
Hydrogen gas is an effective alternative that could be produced from industrial wastes. This makes it one of the cheaper entities where the production cost becomes minimal. Hydrogen also has a high fuel value producing more than 140 kJ of energy. Also upon combustion, hydrogen produces pure water thus putting an end to the increase in the production of greenhouse gas. Hence, hydrogen alone could be an effective alternative that could quench the quantum of energy produced.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 3FB
In batch and continuous fermentative system the process of formation of product remains same. The factor that differentiates the systems is the volume of fermentative medium. In case of a batch system, volume remains the same through fermentative process. But, as far as the continuous system is concerned, volume of the fermentative liquid varies.
Additionally, in a continuous system, as soon as the product is formed it would be removed, and the volume displaced would be replaced by fresh medium. Hence, for both the process the equipment prepared would enable both batch and continuous fermentation to be performed.
The two types of industrial fermentation equipment are designed for batch production or continuous production.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 3M
Potable water is referred to the water sample that is necessary for drinking. Moreover, potable refers to free organic and microbial contamination that makes it safe entity, for consumption. Thus, it could be ascertained that sample that is fit to drink is potable.
Therefore, the statement, “refers to water that is fit to drink” matches with the term, “portable.” Hence, the correct option is G. Potable.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 3MC

  • Uncooked ground meat and fruit are highly perishable. Cheese comes next in the hierarchy which is semi-perishable food stuff. Pasta comes under non-perishable food stuff. Thus the right option is (c) uncooked ground beef, fruit, cheese, pasta.
  • In the view of sorting out foods, which are perishable to nonperishable, option (a) contains pasta as the first one, which is a nonperishable food. Hence, the option (a) is incorrect.
  • Pasta is one of the nonperishable food stuff. Since, it falls last in the hierarchy of food when arranged from a perishable to the non-perishable food. Hence, the option (b) is incorrect.
  • Though uncooked meat and fruit can be included in highly perishable foods, the inclusion of a non-perishable food (pasta) ahead of the semi-perishable food (cheese) makes the option (d) incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 3MTF
Pasteurization is the process of subjecting the food to a short term pulse of heating process that would aid in the removal of pathogenic microbes from the food involved. This process was named after the Louis Pasteur for his work on pasteurization process. Pasteurization is intended to reduce the number of viable pathogenic organisms.
Pasteurization is capable of reducing all the vegetative cells including the mesophiles and other pathogenic strains. The microbial load after pasteurization reduces significantly.
Since, pasteurization is a short time pulse of heating process; it cannot reduce the bacterial endospores, which are more heat resistant. Hence, the given statement is True.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 4CT
Insects feeding on non-Bt (Bacillus thuringiensis) plants produces more offspring’s than those that feed upon Bt plants. This creates a chance for a breeding between the insects that feed upon Bt plants and non-Bt plants, since they are adjacent to each other. The genes that are responsible for imbibing resistance to the Bt plants would thus be diluted when they are multiplied. The chances dominant gene occurring in the insect becomes reduced. This is the reason why the dissemination of resistance to Bt-toxin could reduce among insects.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 4FB
Potable water is referred to the water sample that is necessary for drinking. It refers to free organic and microbial contamination that makes it safe entity, for consumption. Since, coliforms are indicators of fecal contamination, it is highly important that the water to be consumed should be free from all the coliforms. Thus, it could be ascertained that sample that is fit to drink is potable. Thus, potable water is allowed to have zero coliforms per 100 ml of water tested.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 4M
Microbial biofilm is formed as a result of the polysaccharide coat, which is formed by microbes. Moreover, they tend to bound microbes to the coat. Biofilms formed by aquatic microbes as the concentration of energy source available to the microbes, becomes very low. Biofilms are formed to cope up with energy requirements and to ensure that they are found near the surface of the water.
Thus, the statement, “community of organisms surrounded by polysaccharides and attached to surfaces,” matches to the term, “biofilm.” Hence, the correct option O. Biofilm.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 4MC

  • Hence, the correct option is (b) synthetic medium made by hand.
  • Corn is a natural substrate that could be used in the production unit, but the microbes have to make use of the nutrient source that is present in corn. Since, not many of the microbes could use corn as a sole source of energy. So, this cannot be used as an effective industrial growth medium. Hence, the option (a) is incorrect.
  • The spent liquid that is formed during cheese production is whey. It contains minimal sugar concentration that could not effectively be used as an efficient source of energy for the microbes, when it is involved in the synthesis of specific products. Hence, the option (c) is incorrect.
  • Brewing mash is said to be waste that is produced after microbial fermentation. Since it is one of the end products after fermentation, it is ascertained that the utilizable sugars that are a part of the source has already been utilized. The remaining solid mashes that cannot further be used for the saccharification of sugars are left out as waste. This cannot be used as an effective source of energy for the microbes that required adequate micro and macro nutrients for their development and product formation. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 4MTF
Methane could be produced as a result of microbial metabolism of the methanogenic bacterial strains. Methane could be combusted directly and could be used as an effective alternative to house hold cooking gas. The only drawback of using methane is that it could add up to the existing carbon dioxide gas that could lead us to global warming. Hence, the given statement is True.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 5CT
First thing that strikes is the ethical factor that prevents us from using the treated wastewater for consumption. This is because the waste water could not only be produced as a result of industrial activities but also as a result of human activities. This leads to the mixing of fecal coliforms with the waste water being treated.
Even though treatment reduces the visible and invisible organic content, the microbes and more precisely the coliforms would not be removed. This makes it a vital reason why treated waste waters are not entering the water treatment used for the development of water consumption.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 5FB
Coal deposits are associated with reduced metal compounds such as pyrite. Strip-mining of coal exposes pyrite to oxygen and microbes oxidizes the iron. When the same component is exposed to bacteria Thiobacillus, they oxidize sulfur. However, the oxidized compounds are leached by rain water, produce sulfuric acid, and iron hydroxide. When the components are washed off through rain water it would lead in reduction of pH of the natural water system enough to kill fish, plants, and other organisms.
Leaching of compounds from mine tailings often results in the oxidation of two elements: iron and sulfur.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 5M
Oxidation lagoon is one that is used in processing of animal wastes. The lagoons accomplish the equivalent reactions of primary and secondary treatment. In oxidation lagoons, wastes would be pumped into deeper parts and are left for three months. As a result of anaerobic oxidation, organic content would be degraded to simpler forms. The liquid wastes developed would be left at the top, for aerobic digestion.
Thus, the statement, “used in the processing of animal wastes, mimics primary, and secondary wastewater treatment,” matches with the term, “oxidation lagoon.” Hence, the correct option is I. Oxidation lagoon.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 5MC

  • Poly-Hydroxy-Alkonate (a polymer) a storage product produced, which is similar in shape to the petroleum based product, could be used as an alternative biodegradable plastic. Hence, the correct option is (b) PHA.
  • Sludge is a component that comes out of the aeration tank. Sludge is a mixture of coarse organic content and microbial biomass. This cannot be used in the formation of biodegradable plastic. Hence, the option (a) is incorrect.
  • Biochemical oxygen demand (BOD) is the quantum of oxygen required by the microbes to reduce organic load in a water sample. BOD indirectly gives the load of organic content that is an integral part of the waste water system. This is in no way connected with biodegradable plastic, making option (c) incorrect.
  • Alum is a chemical that is used as a flocculation agent that aids in the removal of solid and other suspended biomass that forms a part of the water. This is one of the primary methods deployed in the treatment of waste water. It cannot be used in the production of biodegradable plastic. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 5MTF
Water treatment is more or less the same for both drinking and sewage water. Both the procedures involve the primary (sedimentation), secondary (flocculation), and tertiary treatment (Chemical treatment) systems. Hence, the given statement is True.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 6CT
Food wastes (including vegetables), waste papers were the components that were predominantly found in the garbage. These components form the compostable wastes, which could be oxidized as by microbial action.
On the other hand glass pieces, plastic bags, and metal pins are those which cannot be composted and that could be recycled. More than 85% of the wastes could be either recycled or could be composted making only about 15% to be left back without being recycled.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 6FB
Biogeochemical cycling involves three primary steps:
production, consumption, and decomposition.
Biogeochemical cycle involves the cycling of chemical elements from an unusable form to usable form. The unusable form would be converted from an inorganic form to an organic form, which would be consumed by the living systems. After the destruction of living system, hosting the chemical element, other microbes would act on it rendering it to be decomposed and form the inorganic component again.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 6M
Xenobiotic compounds are man-made and are non-biodegradable by the microbes. When the concentration of the compounds is high in the environment, leads to pollution in the environment. However, the compounds are insoluble and highly stable. Moreover, most of the compounds of xenobiotic are non-degradable and recalcitrant in nature.
Therefore, the statement, “refers to compounds that are resistant to microbial degradation,” matches with the term, “recalcitrant”. Hence, the correct option is J. Recalcitrant.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 6MC

  • Pseudomonas syringae produces a protein that is involved in the formation of ice crystals. The product is such that, the microbe could thrive even without the formation of ice crystals. Thus, when microbe is developed, which is devoid of this gene, even when the microbe is grown on plants it could prevent the plants from freeze damage. Hence, the correct option is (d) prevention of ice formation.
  • Non-biodegradable plastic could be replaced by the more biodegradable plastic in the form of storage product that is produce by microbes. Pseudomonas syringae are not used in the production of products thus making option (a) incorrect.
  • Alternative fuels in the form of methane, ethanol or hydrogen could be produced by other strains of microbes including Bacillus. Hence, the option (b) is incorrect.
  • Fermentation is the process of converting soluble sugars in the system to alcohol. Primarily fermentation is done through Saccharomyces strain. Thus, it could be ascertained that option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 6MTF
Recalcitrant molecules are highly non-biodegradable and are man-made molecules. Very rarely, naturally occurring microbes could act directly on recalcitrant components, rendering them inactive. The enzyme that possess properties, but which are not used for the purpose, is used in degradation process. For example, laccase is used in the decolorization of textile dyes. Moreover, laccase is in no way connected to decolorization, but its services could be incorporated in environmental management. Thus, the statement, “recalcitrant molecules are degraded by naturally occurring micro-organism,” is true.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 7CT
Water treatment through the different stages removes the solid organic wastes as well as microbes (predominantly coliforms), thus enabling it potable. When such potable water is consumed, there are least opportunities for the microbes to gain access in to the human system that could probably elicit a disease. Also most of the microbes that are soil borne is not specifically pathogens and the natural barrier (skin) that would prevent the entry of microbes, thus eliminating the chance of a microbial infection.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 7FB
Nitrogen exists primarily as dinitrogen gas (N2) in the environment.
Nitrogen exists as a dinitrogen gas possessing a triple bond in between the two nitrogen atoms. The dinitrogen gas is an inorganic form of nitrogen. The triple bond requires high energy to be broken down. Hence, the conversion of inorganic nitrogen to its organic form becomes an all-important process in the entire living systems.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 7M
Water activity is the presence of water molecules that are devoid of binding to solute particles. The higher the water activity, the greater would be the chance for the microbes to thrive. Hence, in food preservation, reduction of water activity by the addition of solutes would always be preferred.
Thus, the statement, “water that is not bound by solutes”, matches with the term “water activity”. Hence, the correct option is B. Water activity.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 7MC

  • Sludge is composed of both coarse particles and microbial biomass. This could be recycled into the effluent for the reduction of organic component in the effluent in an aerator. Hence, the option (a) is incorrect.
  • Poly-hydroxy-alkonate (PHA) is an alternative form of plastic that is biodegradable. This is formed as a result of storage products of microbes within their cell. Hence, the option (b) is incorrect.
  • Biochemical oxygen demand (BOD) is the measure of organic content present in a water source. This is in no way connected with flocculating organic particles. Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 7MTF
Biofilm is a complex aggregation of microorganisms, like bacteria. They may be harmful and beneficial. Additionally, biofilms keep microbes intact with each other and with solid surface near the shores, for acquiring nutrients. It is a phenomenon found common in aquatic microorganisms. Without the formation of biofilm, the microbes find it difficult to adhere to solid substrates.
Thus, the chances of the microbes acquiring nutrient, in the vast land scape of the aquatic arena also gets reduced. For instance, some of the bacterial biofilms are present on the surface of the teeth and tongue. Hence, the given statement, “biofilms of microorganisms form in aquatic environments only” is true.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 8CT
Influenza viruses are capable of producing new antigenic determinants over a period of time. This process ensures that the human system does not have a premeditated immunity in the form of memory cells, thus making it a deadly component. This is the main reason why influenza virus could be used as a devastating biological weapon.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 8FB
Phosphorus exists primarily as phosphate ion in the environment.
Phosphorus undergoes little change in the oxidation state in the environment. It usually exists in the form of phosphate ion in the environment. Phosphorus cycle involves the conversion of the inorganic form to the organic form. The conversion takes place through microorganisms and from the organic to inorganic form through pH-dependent process.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 8M
Biomass is the quantum of organisms that is present in a particular locality. The concentration of biomass could always be decisive factor in industrial fermentation. The ecosystem on planet earth form biosphere. Moreover, the term biodiversity defines the number of species living in a given ecosystem. However, biomass refers to quantity of all the species.
Thus, the statement, “refers to quantity of all organisms present in an environment,” matches with the term, biomass.” Hence, the correct option is K. Biomass.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 8MC

  • Though chemicals could have a deleterious effect on microbial cells, it cannot have an effect on viruses. This is because; viruses are obligate, intracellular parasites. They don’t have any cell bodies, and internal organelles to be effected by chemicals. Thus the right option is (b) viruses.
  • Tertiary treatment through chemicals reduces the microbial load by a greater extent. Chlorination of the water system reduces bacteria, fungi, and algae. Thus it could be ascertained that algae would be depleted by the action of chemicals. Hence, the option (a) is incorrect.
  • Fungal spores could also be removed as a result of chemical treatment. Bacterial endospores, viruses, and protozoan cysts are not supposed to be deactivated by chemical treatment. Hence, the option (c) is incorrect.
  • Bacteria are susceptible to the action of chlorination. Chlorine completely removes the entire component of the bacteria, thereby proving that option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 8MTF
Microbes are non-cooperative, unless they depend on one another for specific reasons. It is a known fact that growth rate of microbes is higher and exists stiff competition for food and shelter in an environment. Thus, provides that they cannot exist through cooperation. Hence, the given statement, “cooperation is common among microorganisms living in micro habits” is False.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 9CT
Any fermentative product that is formed from fruits tends to be called a wine and those whose initial ingredients becomes grains, produces beer. Since rice is a grain, the fermentative product that is formed as a result of rice fermentation could be called a rice beer instead of “sake” (rice wine).

Microbiology with Diseases by Taxonomy Chapter 26 Answers 9FB
A biosensor is a device composed of microbes and electronics used to detect other microbes or their products.
One of the new applications about microorganisms pertaining to the solving of environmental issues is the biosensor. Biosensors involve the microbes or microbial products in contention with electronics. This process enables the presence of certain microbes or their products. Sensors could be used to serve as early warning system to give officials more time to respond to a possible terror attack.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 9M
Eutrophication is a process in which, water gets polluted in a number of ways paves way for other organisms to thrive on them. This leads to the reduction in the oxygen level (as the final electron acceptor in respiration of organisms that lead to oxygen reduction) of the entire water system, putting the indigenous organisms under great stress.
Moreover, an excess growth of microorganisms in aquatic system result in more nitrogen and phosphorus that acts as fertilizers. This results in the growth of microbes with depletion of oxygen.
Thus, the statement, “process whereby pollutants accumulate to high levels in waterways, causing overgrowth and anaerobic conditions,” matches with the term, “N. Eutrophication.” Hence, the correct option is N. Eutrophication.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 9MC

  • It is during the secondary treatment stage that most of the organic content is reduced. The total solids that comprise the dissolved and suspended organic content would be reduced by the action of microbes in the aeration tank. Thus the right option is (b) secondary treatment.
  • During sewage treatment, the primary treatment aids in the removal of solid coarse particles from the waste water. Since, only the coarse particles are removed from the system, option (a) is incorrect.
  • During tertiary treatment the organic load in the form of microbes alone would be removed from the system. This would be only a limited reduction in the organic load on compared with the efficiency of the entire treatment system. Hence, the option (c) is incorrect.
  • Sludge treatment is a separate system that deals with the reduction of sludge that is being developed in a separate process. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 9MTF
Microorganisms thrive well in aquatic environment, primarily near the shores and at the topmost layer of the system. As the depth increases in the water system, the microbial density reduces proportionately. This is because in cold environments the concentration of biomass and metabolic activity is dominant. Thus, the low temperature for organism facilitates the production of energy and organic carbon.
Hence, the given statement, “aquatic microorganisms are more prevalent near the surface than at the bottom of waterways” is true.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 10CT
Wine when exposed to air becomes an excellent source of energy for microbes. This would enable the microbe to populate in the wine and initiate their metabolic activity. Microbial metabolic action would convert ethanol to acetic acid, thus creating a vinegary taste or a smell when wine is consumed (vinegar is said to be composed of 4% of acetic acid).

Microbiology with Diseases by Taxonomy Chapter 26 Answers 10FB
Biochemical oxygen demand (BOD) is the amount of oxygen required by aerobic organisms to fully metabolize organic waste in water.
Waste water would be full of organic content, which could be quantified indirectly by the process of biochemical oxygen demand. In this process, the waste water would be added to oxygenated water as a seed. This would be left as such for about 5 days at specific temperature range. After incubation, the difference between the initial and the final oxygen concentration would be equivalent to the load of organic content present in the waste water sample.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 10M
Nitrogen fixation is a process through which the atmospheric inorganic nitrogen would be fixed by the action of nitrogen into usable forms of organic nitrogen (ammonia). Nitrogen fixers are called as alphaproteobacteria, which grow in association with the roots of plants. Moreover, convert atmospheric nitrogen to ammonia and make it available for plants as fixed nitrogen. Nitrifying bacteria derive electrons from the oxidation of nitrogenous compounds.
Hence, the statement, “process of reducing nitrogen from atmosphere,” matches with the term, “nitrogen fixation.” Hence, the correct term is M. Nitrogen fixation.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 10MC

  • Microbial communities can never be composed of a single pure population of microbe. Microbial community is composed of many different species of organisms. Hence, the option (a) is incorrect.
  • A microbial community cannot represent all the microbes present in a locality. Since, a locality could be differentiated based on various physical and chemical characteristics, there is a greater probability that certain microbes cannot thrive in a particular environment. Hence, the option (b) is incorrect.
  • A biosphere is an arena where the entire area is made up of all the possible living organisms. Since, it involves all the living organisms, option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 10MTF
The littoral zone exists between high tide and low tide region. Moreover, the littoral region acts as a transition zone existing between the terrestrial and marine ecosystem. However, the organisms that are found near the shores of the oceans are littoral organisms and not the abyssal organisms. Abyssal organisms that are those that are found near the hydrothermal vents found at the bottom of the ocean.
Thus, in littoral zone the ecosystems existing includes the following; estuaries, mangrove forests, and salt marshes. Hence, the given statement, “abyssal organisms that are found near shores of oceans” is false.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 11M
Antagonism is the characteristic feature of the organism that prevents itself from the action of other microbes in the vicinity by the production of certain metabolites. In other words, it is an interaction one species get benefitted by the expense of another. For example, bacteria thrives in human body do harm to the host. Hence, the given statement matches with option (L) Antagonism.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 11MC

  • An environment is said to be a vast space where generally the nutrient is supposed to be considered very limiting compared to the quantum of living organisms present. This proves that option (a) is the right choice.
  • Nutrients cannot be present in excess in the environment considering its vast area. To have an excess load of nutrient in an environment equivalent to feed the living organisms, the nutrient should be present ubiquitously. Thus, option (b) is rendered as the incorrect choice.
  • In an environment of fluctuating physical conditions, the quantum of nutrient present always modifies. Sometimes the microbes tend to utilize nutrients slowly and at other times it tends to use them more vigorously for their growth and development. This shows that nutrient level in the environment is not stable, thus proving option (c) as the incorrect choice.
  • Nutrients in the environment are due to the action of the primary producers that are able to photosynthesize. It is from these primary producers the nutrient flows to the consumers. Since the fixation of carbon by the primary producers is a natural process, option (d) becomes an incorrect option. Thus, the right option is (a) limiting.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 12M
Spoilage is the term used to denote the undesirable changes in food occurring as a result of activity of microbes. On the other hand a desirable change in the component of the food is termed fermentation. Hence, the given statement matches with the option (A) Spoilage.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 12MC

  • Minerals like phosphorus and sulphur are found in an unusable format in the form of soil and rock. Even though it trickles from these rocks, it should be converted to usable form by microbial action. This shows that option (a) is not the right choice.
  • Any mineral is required by the living organisms in limited quantum to make sure that the bodily activities are performed in the right balance. Minerals cannot be found in a usable form in water because it then becomes so adequate that we need not bother about its presence. Thus, it could be ascertained that option (b) is the incorrect choice.
  • Most of the minerals are present in unusable forms in soil and rock. The conversion of the unusable form to usable form requires the action of living organisms. This shows that option (c) is the right choice.
  • Water cannot be a source of most chemical elements, as it would increase the total dissolved solids in the system that would have other deleterious effects on aquatic living forms. This shows that option (d) cannot be the right choice. Thus, the right choice is (c) unusable forms in soil and rock.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 13M
Pasteurization is the process of subjecting the food to a short term pulse of heating process that would aid in the removal of pathogenic microbes from the food involved. This process was named after the Louis Pasteur for his work on pasteurization process. Pasteurization is intended to reduce the number of viable pathogenic organisms. Hence, the given statement matches with the option (D) Pasteurization.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 13MC

  • In a carbon cycle microbe uses chlorophyll and sunlight to fix carbon dioxide present in the atmosphere into usable form of organic component. This shows that option (a) is the right choice.
  • Carbon dioxide is the inorganic form of carbon, which when fixed by the microbes takes the organic form in the form of carbohydrates. This proves that option (b) is an incorrect choice.
  • Carbon cycle is the conversion of inorganic form of carbon (carbon dioxide) to useful forms of carbon in the form of carbohydrates (organic). Fossil fuel is formed as a result of action of heat and pressure on decayed organic content. This shows that option (c) cannot be the right choice.
  • During the process of photosynthesis carbon dioxide will be fixed to an organic carbohydrate form. The process utilizes water molecule that would at the end form oxygen, proving that option (d) is the incorrect choice.
    Thus, the right option is (a) convert CO2 into organic material for consumption.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 14M
Biochemical oxygen demand (BOD) gives the quantum of organic material present in a sample through indirect means. The organic load would be allowed to act upon by microbes (seed) that would reduce the oxygen level in the system. The level of reduction in the oxygen in the system is directly proportional to the quantum of organic load present in the system. Hence, the given statement matches with the option (H) BOD.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 14MC

  • The process of converting organic nitrogen ammonia is termed nitrogen fixation, which involves the usage of the enzyme nitrogenase. This shows that option (a) is not the right choice.
  • The conversion of ammonia to NH4+ is through a process termed ammonification. This shows that option (b) is incorrect.
  • Nitrification is a process that is characterized by the conversion of NH4+ to nitrate ions (NO3). This proves that option (c) is the right choice.
  • The process through which nitrite is converted to nitrogen gas is termed as denitrification. Hence, option (d) cannot be the right choice. Thus, the right choice is (c) converts NH4+ to NO3.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 15M
Secondary metabolites are those that are produced when the microbial biomass enters the stationary phase. Antibiotics and other such substances are produced during this phase to enable the microbe to survive against other microbes in the vicinity. Hence, the given statement matches with the option (E) Secondary metabolites.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 15MC

  • In aquatic environment, most microorganisms were found occupying the littoral zone, mainly because of the rich nutrients prevailing as it is near the shore. This shows that option (a) is the right choice.
  • The limnetic zone is found next to the littoral zone that is the shallow or the top most portion of the aquatic environment. The limnetic zone is said to comprise the photosynthetic primary producers. This shows that option (b) is incorrect.
  • The profundal zone is found just below the limnetic zone. The penetration of light in this area reduces with depth proving that there would be a gradual reduction in the quantum of microbes present. This shows that option (c) is incorrect.
  • The benthic zone is the deepest part of the aquatic environment, which is devoid of light and nutrients and as a result, the microbial population do not grow well. This shows that option (d) is incorrect.
  • The abyssal zone has nothing, but the hydrothermal vents that are formed at the base of the oceans. Presence of life at this point is expected to be nil proving that option (e) is incorrect. Thus, the right option is (a) littoral zone.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 16MC

  • Small pox is caused by a category ‘A’ biological weapon, which is categorized as one of the most dangerous animal pathogen. Small pox is caused by the Orthopoxvirus. Hence, option (a) cannot be the right choice.
  • Plague is caused by Yersinia pestis, a bacterium which is categorized under the type ‘A’ biological weapon. Hence, option (b) cannot be the right choice.
  • Q fever is a bacterial disease caused by Coxiella burnetii. The organism is categorized under the moderately dangerous category ‘B’ biological weapon. This shows that option (c) should be the right choice.
  • Talaremia is a bacterial disease caused by the organism Francisella tularensis. The organism and the disease come under category ‘A’ biological weapon, thus showing that option (d) is the incorrect choice. Thus, the right option is (c) Q fever.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 17MC

  • Microbes that are readily available in the environment make it an efficient component to be used as a weapon than the one that is highly a rarity. But this option would enable the scientist that when a rare species is used the attack it could be easily identified as an attack. Hence, option (a) cannot be the right choice.
  • When the initial impact is huge it could lead to the spread of disease through the secondary and tertiary wave that could be fatal. This is a major criterion that could lead to huge number of casualties. This could be an effective reason making option (b) as the right choice.
  • It is not necessary that the microbes should be treated within the hospital system, but could also be treatment of the patients outside the hospital as well. This shows that option (c) is incorrect.
  • Symptoms are characteristic features that could be identified as a result of the disease caused by the microbes that is spread. The faster the symptoms appear the faster would be the action of the doctors against the microbes. Hence, option (d) cannot be the right choice.
  • Thus, the right option is (b) can be spread by contact after original dissemination.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 18MC

  • Anammox reaction is characterized by the oxidation of ammonium to nitrogen gas using nitrite as an electron acceptor. It is an abbreviation for anaerobic ammonium oxidation. It is an important microbial process for nitrogen cycle and plays significant role globally. Hence, option (a) should be the right choice.
  • Anaerobic reaction in the case of carbon cycle leads to the formation of carbon dioxide and methane gas. Thus, it could be ascertained that option (b) cannot be the right choice.
  • In sulfur cycle, the anaerobic reaction leads to the formation of H2S from sulfate. Hence, option (c) cannot be the right choice.
  • The processing of metal oxidation enables the unusable forms of metals to be converted to usable forms of metals for life activities. This shows that option (d) cannot be the right choice. Thus, the right option is (a) anaerobic and part of nitrogen cycle.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 19MC

  • Industrial fermentation is the formation of a desired product through large scale production unit that involves microbes.
    Ethanol production cannot be the only product that is developed through industrial fermentation, thus making option (a) as the incorrect choice.
  • Industrial fermentation refers to the production of product of interest employing large scale units. This proves that option (b) is the right choice.
  • Process of oxidation and reduction are a part of microbial activity irrespective of the volume of the source used. Hence, option (c) cannot be the right choice.
  • A desirable change in the food by microbial metabolism is as a result of fermentation. This proves that option (d) is incorrect.
  • Thus, the right option is (b) involves the large-scale production of any beneficial compound.

Microbiology with Diseases by Taxonomy Chapter 26 Answers 20MC
Lyophilization is a process of freeze drying the contents. In Lyophilization, the contents would be frozen first and then the water molecules would be removed through vacuum suction. This process is otherwise called cryodesiccation, as dehydration is involved in this process.
Since cell lysis, or use of gamma radiations, or rapid heating is not observed in lyophilization, the options (a), (b), and (c) cannot be the right options. Thus, the right option is (d) freeze-drying.

Microbiology with Diseases by Taxonomy Chapter 25 Answers

Microbiology with Diseases by Taxonomy Chapter 25 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 25 Answers 1CM
Polioviruses belong to the genus Enterovirus. These enterovimses are transmitted by fecal-oral route.
microbiology-with-diseases-by-taxonomy-chapter-25-answers-1cm

Microbiology with Diseases by Taxonomy Chapter 25 Answers 1CT
RSA(ribonucleic acid) viruses are grouped into 15 families. Moreover, positive single stranded RNA viruses are classified into eight families and negative single stranded RNA viruses are classified into six families. Among them only one family is having double stranded RNA viruses.
The dichotomous keys for 15 families of RNA viruses are listed below:
microbiology-with-diseases-by-taxonomy-chapter-25-answers-1ct
microbiology-with-diseases-by-taxonomy-chapter-25-answers-1ct1

Microbiology with Diseases by Taxonomy Chapter 25 Answers 1L
The steps in retroviral replication in HIV are as follows:

  1. The HIV (human immune virus) attaches itself to the cell and penetrates.
  2. It is uncoating itself.
  3. Synthesis of dsDNA takes place and the virus enters the nucleus.
  4. Latency – The virus may remain dormant for years or can be activated soon.
  5. Synthesis – Viral particles are synthesized
  6. Assembly and budding – Two RNA molecules make a new virion with the enzymes reverse transcriptase, and integrase and two tRNA molecules. The virions bud from the cytoplasmic membrane.
  7. Maturation of the virion – Protease releases reverse transcriptase and capsomeres. This makes the HIV virulent.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 1M

  • The term myocarditis matches with the term (K) Picornaviridae. Encephlomyocarditis virus belonging to cardiovirus genus causes encephalomyocarditis in pigs. Piglets which get this infection show encephalitis and myocarditis and die suddenly.
  • The term Colarado tick fever matches with the term (C) Reoviridae. This disease is caused by coltivirus of family Reoviridae. This virus is an arbovirus causing a zoonosis called Colarado tick fever. This disease is transmitted by ticks.
    The term Rabies matches with the term (A) Rhabdoviridae. Rabies virus belongs to the family Rhabdoviridae. This disease is a zoonosis of mammals. The animal reservoir is dog in urban areas. Foxes, bats, and cats also are reservoirs of this virus in the wild areas.
  • The term influenza matches with the term (G) Orthomyxoviridae. This disease is caused by two species of family Orthomyxoviridae. It has host such as vertebrates, pigs, birds and horses, and mammals. Vertebrates include humans also. Air-borne viruses spread the infection and also through fomites.
  • The term Dengue fever matches with the term (F) Flaviviridae. A virus belonging to the family Flaviviridae causes dengue fever. This is transmitted by Aedes mosquito. This is also called breakbone fever because of the severity of the pain.
    The term German measles matches with the term (D) Coronoviridae. This disease is caused by Rubella virus. It is a childhood disease and cause rashes. As the German scientist found out that it is a separate disease, this is named as German measles. It is infectious only to humans.
  • The term acute gastroenteritis matches with the term (I) Calciviridae. Calciviruses cause acute gastroenteritis. They infect humans through digestive route and cause this disease. It causes outbreak of gastroenteritis in schools and day care centers.
  • term Ebola virus matches with the term (J) Filoviridae. Ebola virus belongs to the family filoviridae and cause haemorrhagic fever. The predominant feature of this infection is that it causes bleeding under the skin and also through every opening of the body. Almost 90% of the humans infected by Ebola virus die.
  • The term RSV matches with the term (B) Paramyxoviridae. This is called Respiratory syncytial virus, which belongs to the genus Pneumovirus and family Paramyxoviridae. It causes lower respiratory infection in young children. It affects the lung and form syncytia. Also dead cells, fibrin and mucus plug block the small air passages causing difficulty in breathing.
    The term Western equine encephalitis (WEE) matches with the term (E) Togaviridae. Togavirus cause this disease. The normal host for this virus is bird.
  • The term ‘No known disease’ matches with the term (H) Orphan virus. The term orphan virus applies to the virus that is not associated with any known disease. The viruses of the family Reoviridae causes diseases of respiratory tract and gastrointestinal system. Previously this fact was not known. Hence, it was called orphan virus with no known disease.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 1MC

  • A segmented genome is one that has more than one strand of nucleic acid. Hence, (a) is the correct option. Negative, enveloped, ssRNA (single stranded RNA) viruses have a segmented genome. The genome in the virus is fragmented into two or more nucleic acid molecules and is packaged into different RNA (ribonucleic acid) segments. Examples of such viruses are flu virus of family Orthomyxaviridae and many viruses in Bunyaviridae and Arenaviridae. They usually infect animals also they can be transmitted to humans.
  • Option (b) is not correct because a segmented genome do not have double-stranded RNA. But they have more than one strand of nucleic acid. Negative sense ssRNA viruses have segmented genome.
  • Option (c) is not correct as a segmented genome does not have both RNA and DNA strands. The negative ssRNA viruses, which belong to the family of Orthomyxoviridae, Bunyaviridae, and Arenaviridae have segmented genome.
  • Option (d) is not correct as a segmented genome does not have +ssRNA and -ssRNA molecules. A segmented genome is present in -ssRNA. Orthomyxoviridae and Bunyaviridae are examples of negative sense ssRNA, which have segmented genome. Hence, the correct option is (a) has more than one strand of nucleic acid.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 1SA
Life cycle of the arboviruses is between a host and a vector. Common vectors are mosquitoes, ticks, sand flies, and other blood sucking arthropods.
During the blood meal, the viruses are injected into the human body by the vectors. Inside the human body the viruses undergo amplification. Due to replication of virus at sufficient levels, viremia is caused. In this condition, there is huge number of viruses in the human blood circulation. Thus, the uninfected vector can ingest the virus during a blood meal and can transmit the virus to an uninfected human.
If viremia is not achieved in the human host, the transmission of the virus to the vector is not possible. This is the dead-end of the virus in the human host.
Humans are considered as dead-end hosts to many arboviruses, as persistent viremia does not occur in humans. They enter the target cells and replicate inside the cells. So, within 3-7 days of infection, mild flu like symptoms appears. This is the initial manifestation and arboviruses cannot go beyond this level.
In some cases, arbovirus in the blood may affect brain, liver, and skin. This is second –stage infection. This may result in encephalitis, yellow fever, and dengue fever.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 1TF
This statement- A single virion is sufficient to cause cold is a true statement.
Even though many viruses cause cold, more than 100 types of viruses of genus Rhinovirus (rhinoviruses) causes cold.
Rhinoviruses are limited to upper respiratory tract. They are very infective. Entry of a single virion is sufficient to cause cold in more than 50% of the exposed individuals.
When the infection is severe, more than 100,000 virons are present in each millimeter of mucus membrane in the nasal cavity. An infected individual spreads the infection by releasing the viruses into the surroundings. From the surroundings it is transmitted by aerosols or through hand contact. Infection occurs through inoculation by hand into the into the mucus membrane of the eye. From the eyes it is washed into the nasal cavity by tears.
So, a single virion is sufficient to cause cold. This statement is TRUE.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 2CT
A 20 year old man is bought to emergency room. He was suffering from seizures, disorientation, hallucinations, and an inordinate fear of water. His family member has reported that he is having a history of headache and fever. Moreover, he was bit by a dog before his admission in hospital.
Diagnosis: The reports of the patient have revealed that he is suffering from rabies.
Treatment: Vaccination at this stage will not be an effective treatment.
Animal reservoirs: Raccoons are source of rabies virus in South Carolina.
Additionally, relatives of the patient who had direct contact with the patient are advised to receive prophylactic treatment. Since, the saliva of the patient has rabies virus and are infective they are prone to get infection.
Thus, the treatment involves rabies vaccine (human diploid cell vaccine) and human rabies immunoglobulin.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 2MC

  • In families Picornaviridae, Caliciviridae, Astroviridae, Coronaviridae, Togoviridae, Flaviviridae, and Retroviridae common feature is that they all have positive single-stranded RNA genomes. They are based on RNA (ribonucleic acid) polymerase. Hence, the option (c) is correct.
  • Option (a) is not correct because all of them are not arboviruses. Arboviruses are the viruses, which are transmitted by arthropod vectors. The genus Alphavirus belonging to family Togaviridae comes under Grorp A arbovirus. Genus Flavivirus belonging to family Flaviviridae comes under Group B arbovirus. Family Picornaviridae also comes under arbovirus.
  • Option (b) is not correct because they are pathogenic viruses. A picornavirus causes common cold, poliomyelitis, and so on. Calicivirus causes acute gastroenteritis. Astroviridae causes diarrhea, vomiting, and fever. Corona viruses cause Severe Acute Respiratory Syndrome. Toga viruses cause chikungunya. Flaviviridae causes yellow fever and dengue fever. Retroviruses cause tumors. Hence, all these families are pathogenic viruses.
  • Option (d) is not correct because they are not negative single stranded RNA genomes. All the above mentioned families have positive single stranded RNA genomes.
  • Hence, the correct option is (c) they have positive single-stranded RNA genomes.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 2SA
Five classical childhood diseases that produce rashes or skin lesions are as follows:

  • Fifth’s disease
  • Chickenpox
  • Rubella
  • Rubeola
  • Roseola

Fifth disease or erythema infectiosum is caused by erythrovirus, which is also called parvovirus B19. It starts with low-grade fever, and cold symptoms. After few days, bright red rash appear on the face.
Chickenpox is caused by varicella Zoster virus. This is a very contagious disease. The early symptoms are low grade fever, and body aches. The disease starts with rashes which start as macules first and then papules and then vesicles. The lesions appear mainly on the body and head and spread to face and limbs. In severe cases, rashes can spread to oral mucous membrane, pharynx, and vagina.
Rubella is caused by rubella virus. Other name for this disease is German measles after the German physicians, who first described this disease. This is a mild form of disease. Rashes appear on the face and then to the trunk and limbs. Within 3 days the rashes disappear. There is mild fever, swollen lymph glands, joint pains and conjunctivitis.
Rubeola is otherwise called measles or red measles. It is a serious childhood disease and more contagious disease. It is caused by a paramyxovirus belonging to genus Morbillovirus. There will be fever for 4 days and cold, coryza and redness of eye are present. The diagnostic sign of measles is koplik’s spots. In many cases, it is not seen because they may disappear in a day.
Roseola is also called roseola infantum. It is caused by Roseola virus. Human herpesvirus-6 and human herpesvirus -7 are collectively called Roseolavirus. It generally affects the children below 2 years of age. It occurs in children between six months to two years of age. Sometimes there may be manifestation of high fever few days before the appearance of rashes.
If a child develops some rashes or skin lesions the question that can be asked to determine the type of virus are as follows.

  • What is the age of the child?
  • Whether the child had fever before the onset of skin lesions?
  • Does the child have cold like symptoms?
  • Are there any rashes in the mucous membranes?
  • Is the child tired and exhausted?

Microbiology with Diseases by Taxonomy Chapter 25 Answers 2TF
This statement- All infections of polio are crippling is not a true statement.
There are four conditions in the infection of poliovirus. They are asymptomatic infections, minor polio, non-paralytic polio, and paralytic polio.
The paralytic polio infection occurs less than 2% of polio infections. In this paralytic polio, the spinal cord and motor cortex are invaded by the virus. Hence, the nerve impulse conduction is limited.
The degree of paralysis depends upon the type of polio virus involved and also the infective dose. The degree of paralysis depends on the health and age of the infected person.
In a condition called bulbar poliomyelitis, the medulla and the brain stem are affected. This results in paralysis of muscles in limbs or respiratory muscles, for which iron lungs were once used.
In some cases of paralysis, the paralysis is lifelong and the person would not be recovered, while in some cases, full recovery occurs after 6 months to 2 years. Hence, the given statement is FALSE.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 3CT
Derivation of the name coltivirus:
Explanation
Coltivirus is the causative organism of Colorado tick fever. The word colti is derived from (Col) orado (ti) ck virus – col+ti = coltivirus. Hence, coltivirus got its name from Coloradotick virus. Moreover, coltivirus belongs to family Reoviridae. It is carried by rodents and is transmitted to humans through tick bites. However, the disease is endemic in Rocky Mountains, Colorado.
Thus, the clinical manifestations of this disease are ocular pain, myalgia, biphasic fever, and photophobia.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 3MC

  • The smallest animal viruses are in the family Picornaviridae. The name itself shows that pico means small. So these viruses are small RNA viruses. They are naked, +ssRNA (positive sense single stranded RNA) viruses with an icosahedral capsid. The size of the viral particle is nearly 27-30 nm. The genome is almost 2500 nm in length but it is packed so tightly. This family is separated into many genera, which have pathogens of animals and humans. Hence, the correct option is (d).
  • The option (a) is not correct because the family Caliciviridae does not have smallest animal viruses. They are non-enveloped single stranded RNA viruses and non-segmented. The length of the viruses is 7.5-8.5 kb. The capsid is 27-40 nm.
  • The option (b) is not correct because the family Astroviridae viruses are not smallest of animal viruses. They are isolated from mammals and avian species like ducks and chickens. They are 28-35 nm in length and they are icosahedral in shape. They are non-enveloped.
  • The option (c) is not correct because the family Togaviridae does not have smallest animal viruses. They are enveloped and form spherical shapes measuring 65-70 nm in diameter. It has +ssRNA strand which is 10,000-12,000 nucleotides long. Hence, the correct option is (d) Picornaviridae.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 3SA
The five kinds of hepatitis mentioned in the chapter 25 are

  1. Hepatitis A
  2. Hepatitis C
  3. Hepatitis D
  4. Hepatitis E
  5. Yellow fever

microbiology-with-diseases-by-taxonomy-chapter-25-answers-3sa

Microbiology with Diseases by Taxonomy Chapter 25 Answers 3TF
This statement – Postpolio syndrome is due to latent polioviruses that become active 30-40 years after the initial infection is not true.
Postpolio syndrome is a crippling deterioration in the muscle function, which was affected by polio and extreme fatigue.
Postpolio syndrome is not by reemergence of poliovirus. It is not an infectious disease or phase, as the patient does not have the virus at this time.
Almost 80% of the people who had recovered from paralytic polio before 30-40 years develop this syndrome.
The cause for this syndrome is the age-related aggravation of nerve damage that occurred at the time of original infection.
So, this syndrome is not due to the latent poliovirus, but due to the aggravation of the nerve damage and it is age-related. There is no poliovirus active during the syndrome. Hence, the given statement is FALSE.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 4CT
Primer is necessary in DNA synthesis of Retroviruses, such as HIV:
Explanation
The primer is essential to convert single stranded RNA (ribonucleic acid) into double stranded complimentary DNA (cDNA). Moreover, double strand cDNA can integrate into host genome by creating an infection that last long and cannot be eradicated. This process is mediated by reverse transcription, catalyzed by an enzyme reverse transcriptase. However, the process occurring in replication of HIV virus of retrovirus can be explained in 3 steps.

  • The RNA-DNA hybrid formed as +RNA genome uses tRNA that is carried by virus as primer for DNA synthesis.
  • The RNA portion of the hybrid is degraded by the enzyme reverse transcriptase and the DNA is left.
  • The enzyme transcribes complimentary DNA strand and dsDNA is formed. Thus, RNA primer is removed. Thus, primer is necessary in DNA synthesis of Retroviruses.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 4MC

  • Rhinoviruses cause more colds. The viruses infect microvilli present in nasal cells crossing the layer of mucus. More than 100 types of viruses of family Picornoviridae in the genus Rhinovirus, cause colds. Hence, the correct option is (a).
  • Parainfluenza viruses cause respiratory infection in children less than 5 years of age. Human pareinfluenza viruses -1, 2, and 3, cause lower respiratory tract infections. HPIV-4 causes mild upper respiratory infection. A condition called Croup is caused by HPIV-1 and 2 in which there is ‘seal bark’ cough, inflammation of larynx, trachea, and bronchi are seen. Hence, the option (b) is not correct.
  • The viruses which belong to subfamily Pneumovirinae are called pneumoviruses. They cause acute respiratory infections. The pneumovirus genus has two members namely, the respiratory syncytial viruses, which affect humans and cattle. The second infects the rodents. Hence, the option (c) is not correct.
  • The bunyaviruses do not cause cold. Many of the bunyaviruses are arboviruses. Humans are infected by the arthropods bites. They cause California encephalitis, hemorrhagic fever, and Rift valley fever. Hantaviruses are one type of bunyaviruses. It causes Hantavirus pulmonary syndrome, which is often fatal. Hence, the option (d) is not correct. Hence, the correct option is (a) rhinoviruses.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 4SA
The Human Immuno Deficiency virus or the AIDS virus destroys the immune system of the body. It causes acquired immunodeficiency syndrome. This is not a disease but a complex of diseases with complex signs and symptoms, with a common cause. Hence, it is called a “syndrome” instead of “disease.”
The resistance of the body gets lowered due to the death of helper T-cells of immune system. So, the body cannot fight against any infections, which results in variety of symptoms and variety of diseases. In this condition even minor illness can be aggravated into serious illness.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 4TF
The statement – as the oral polio vaccine contains line attenuated viruses, mutations of these viruses can cause polio – is true.
The oral polio vaccine was produced by using attenuated virus. The major drawback in the oral polio vaccine is that, it has the ability to revert to a form that can cause neurological infection and result in paralysis.
The disease caused by VDPV (vaccine-derived poliovirus) cannot be differentiated from the disease caused by wild virus. Even though it is a rare occurrence, some cases have been reported. This occurs in places where there is low coverage of oral polio vaccination.
Because of the iatrogenic effect of oral polio vaccine, nations turn from the oral polio vaccine to the injected vaccine. Hence, the given statement is TRUE.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 5CT
Alligator’s infections:
Explanation
The alligator hide is very thick that mosquitoes cannot inject the West Nile virus into it. But, as the virus is an arbovirus, infects the migratory birds through mosquitoes. Moreover, birds in turn get infection and animals, which consume infected dead birds, get infected. This may be the case of alligators.
Therefore, the alligators that feed the infected birds are prone to get infection.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 5MC

  • Arboviruses are viruses, which are transmitted to humans by arthropods. The onset of symptoms takes 3-15 days after exposure to the virus. The life cycle of these viruses is between the host and the vector. Common vectors are sandflies, mosquitoes, and ticks. Most togaviruses and flaviviruses are arboviruses. There is no taxonomic significance to the term arbovirus. The arboviruses may be +ssRNA, -ssRNA, and dsRNA. Hence, (c) is the correct choice.
  • The zoonotic pathogens are not arboviruses. They are viruses, which cause diseases in animals that spread to humans. They are transmitted between the animals and humans sometimes by vectors. The arthropod vectors get infect with the arboviruses and infect the humans. But, in humans persistent viremia does not occur readily. So, humans become the dead end of zoonotic viruses. Hence, the option (a) is not correct.
  • Arboviruses are not deactivated viruses used for vaccines. Viruses are grown in culture and then killed using chemicals like formaldehyde or heat. In this method the virus cannot multiply, but it can be recognized by the immune system as its capsid proteins are intact. So, response is evoked. So these deactivated viruses are used in vaccines. Hence, the option (b) is not correct.
  • Arboviruses are not found in arbors. These are viruses, which are transmitted by arthropods. Hence, the option (d) is not correct.
  • Hence, the correct option is (c) Viruses that are transmitted to humans via the bite of an arthropod.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 5SA
Influenza had been a deadly killer disease caused by flu virus. This pandemic disease can cause death in millions. Global deaths are 500,000 annually. This virus causes the death of epithelial cells and the lungs are exposed to bacterial infections. Many dead cells in the lungs cause death.
Flavivirus causes Yellow fever. This results in the degeneration of heart, liver and kidneys. Also intestinal hemorrhage occurs. The mortality rate is more than 20%. Yellow fever epidemics ravaged in America, Spain and West Africa. Globally there are about 30,000 deaths annually due to yellow fever.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 5TF
The statement – A typical host for a togavirus is a horse is a true statement.
Different types of togaviruses cause different diseases. Venezuelan equine encephalitis (VEE) is caused by this virus. The replication of the virus occurs in the brain of the horses and humans.
The vectors are Aedes and Culex mosquito. Natural hosts of this virus are rodents and horses.
This virus affects all the equine species like horses, zebras, and donkeys. After being infected by this virus the equines die suddenly.
The infected equines are the primary animal species that spread the virus. They develop large quantity of this virus in their blood circulation. When a mosquito bites the animal, the viruses are transmitted. Hence, the given statement is TRUE.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 6MC

  • Negri bodies are associated with rabies. They are seen in the cytoplasm of nerve cells infected with rabies virus. They contain ribonuclear protein of the rabies virus. Postmortem laboratory tests are done to determine the presence of rabies virus in suspected animals. One such test is identification of negri bodies in the brain. Hence, the correct option is (d).
  • Negri bodies are not associated with Marburg virus. These Marburg viruses cause viral hemorrhagic fever in humans and primates. Hence, the option (a) is not correct.
  • Negri bodies are not associated with hanta virus. The hanta virus infects humans with rodent saliva, urine, or feces. Some types of hanta virus cause Hantavirus pulmonary syndrome and Hantavirus hemorrhagic fever with renal syndrome, which are fatal diseases in humans. Hence, the option (b) is not correct.
  • Negri bodies are not associated with coltivirus. Coltivirus belongs to Reoviridae family. It causes Colorado tick fever. Hence, the option (c) is not correct. Hence, the correct option is (d) rabies virus.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 6SA
The given statement is incorrect.
Rubeola is called measles or red measles. It is one of the five classical diseases of childhood. Measles is caused by measles virus of the genus Morbillivirus of family Paramyxoviridae.
It is a highly contagious disease and serious childhood disease. It spreads by coughing, sneezing and also by personal contact.
The clinical manifestations are fever, sore throat, cough, conjunctivitis and headache. After two days Koplik’s spots appear on the mucous membrane of oral cavity. Red maculopapular skin lesions appear on the head and body. They fuse together to form huge rashes. This disease may result in death.
Rare complications are pneumonia and encephalitis. Most serious complication is subacute sclerosing panencephalitis (SSPE). This disease starts 1-10 years after the initial infection, lasts for few years and results in death. It has become much rarer disease due to vaccination in children.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 7MC

  • Breakbone fever or Dengue fever will be affected if mosquitoes are eradicated from an area. This is caused by a flavivirus. This dengue virus is transmitted by mosquitoes belonging to several species of Aedes. The patient suffers with fever, pain in head, back, and muscles. The pain is so much that it is called breakbone fever. Once the mosquitoes are eradicated from an area, there will not be any mosquito vector to transmit the virus. Hence, the option (d) is correct.
  • Mumps would not be affected if mosquitoes in one area are eradicated. Mumps is caused by mumps virus. They are transmitted by respiratory secretions. If an infected person coughs, the droplets enter the eyes, nose, or mouth of other person. By sharing water and food also it can spread. They survive on surfaces and can be transmitted by contact. So, mumps do not need mosquitoes for transmission. Hence, the option (a) is not correct.
  • Measles would not be affected by the eradication of mosquitoes. Measles is caused by measles virus. It is transmitted by respiratory droplet infection. Different actions like coughing, talking, and sneezing spread the virus via droplets in the air. Hence, the option (b) is not correct.
  • Hepatitis E is caused by hepatitis E virus. It is transmitted by fecal-oral route. It is fatal to pregnant women about 20%. This can be prevented by personal hygiene, good sanitation there by stopping the fecal-oral route transmission. Hence, the option (c) is not correct. Hence, the correct option is (d) break bone fever.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 7SA
The given label is B/Kuwait/6/10 (H1N3).
Here,
B denotes → type B influenza virus.
Kuwait → location Of original identification.
6/10 → Date Of original identification.
HIN3 denotes the strain of the virus → HA and NA antigens.
So, this label can be translated as influenza type B, in Kuwait, in June 2010, that contains HA and NA antigens of type I and type 3.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 8MC

  • Koplik’s spots are oral lesions associated with measles. These spots are manifested in the mucous membrane of the mouth. They look like grains of salt surrounded by red halo. These spots are definite diagnosis of measles. Hence, the option (b) is correct.
  • Koplik’s spots are not associated with mumps. In mumps, parotid salivary glands get enlarged and painful. Hence, the option (a) is not correct.
  • Koplik’s spots are not associated with flu. Influenza is called flu. It is caused by RNA viruses called influenza virus. The common symptoms are fever, sore throat, muscle pain and chills. It is a severe disease but it can be confused with common cold. Hence, the option (c) is not correct.
  • Koplik’s spots are not associated with colds. Cold is considered as common cold. It is infectious disease of the upper respiratory tract caused by viruses. The clinical manifestations are cough, sore throat, and fever. It affects the nose, throat, and sinuses primarily. Hence the option (d) is not correct.
    Hence, the correct option is (b) Measles.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 8SA
Candidate viral diseases to be eliminated are
Measles – It affects specifically humans. It does not have any animal reservoir. It is a self-limiting disease and it is contagious only for a week. It has got effective vaccination. As it is so more contagious than smallpox and because of the repeated reintroduction of infection the country wide elimination does not have good outcome.
Rubella – It specifically affects human, with no animal reservoir and a good vaccination. It is a self-limiting disease. The eradication of Rubella needs intensive campaign. The difficulty of diagnosis is also a problem in eradicating this disease.
Hepatitis B – it is specifically human pathogen and has got a good vaccine. It is a disease of many persons. People, who get infected in infancy, are persistent and repeated source of this virus. So for eradicating this disease, all the countries should start it early.
HIV (Human immuno deficiency virus) or AIDS (Acquired immuno deficiency syndrome) virus once infects a cell, the genetic material is incorporated into that cell and it lasts for the life time of the cell. The currently available antiretroviral drugs do not destroy the virus and also do not remove the genetic material incorporated into the cell. As HIV shows latency, it gets reactivated anytime. Several years of antiviral therapy is not of much help because the latent HIV infection persists for longer years in some types of macrophages and CD4 cells. So, eradication of AIDS virus is still yet not possible.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 9MC

  • Zoonoses are animal diseases that spread to humans. This may be parasitic, bacterial, fungal, or viral. The emergence of a pathogen into a new host is called emergence of diseases. Rabies and dengue fever are some examples of zoonoses. Hence, the option (a) is correct.
  • are diseases specifically transmitted by mosquitoes and ticks. This option (b) is not correct. The zoonotic diseases can be transmitted by bats, cats, cattle, mice, pigs, and so on. There are so many zoonotic infectious organisms.
  • Option (c) states that zoonoses agents are mucus borne viruses, which are transmitted in the droplets of moisture in a sneeze or cough. This is not correct option. These infectious agents that cause zoonoses are transmitted by vectors or by contact with the animals. It is may be droplet mucus borne rarely as in the case of rabies. The rabies virus in the saliva of infected animals is transmitted through a bite or through the cut or break in the skin, or through inhalation which is rare.
  • Option (d) states that zooneses are diseases that can be transmitted from humans to an animal population. This is not correct option. In the case of anthroponosis, a disease causing agent, which is carried by humans are transmitted to other animals. Hence, the correct option is (a) they are animal diseases which spread to humans.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 9SA
The common tests for detection of viral diseases:

  1. Antibody test- to find the antibody specific to the viral infection. This test is done with the blood sample.
  2. Viral antigen detection test- this is to find the viral antigens develop on the surface of the infected cell. This test needs the tissue sample.
  3. Viral culture- viral culture may take weeks for growth.
  4. Viral DNA (deoxyribonucleic acid) or viral RNA (ribonucleic acid) detection test- it is to find the genetic material of the virus involved. The sample of tissue or spinal fluid or blood can be used for this test.

The most common tests dealt in chapter 25 are

  • Serological test like ELISA (Enzyme linked immunosorbent assay) and agglutination of latex beads to which the arbovirus antigens are fixed. This is the test for arboviruses.
  • For HIV (human immuno deficiency virus) infection, PCR –Polymerase chain reaction is done. Definite diagnosis can be done with this test. Serological tests like ELISA, agglutination, western blot testing is done that can reveal antibodies against HIV. The positive test for antibiotics just shows that the patient was exposed to HIV.
    In the case of measles, serological tests confirm the measles antigen in blood and respiratory samples.
  • For Respiratory syncytial virus, immunoassay is done. Respiratory fluids are tested for immunofluorescence, ELISA and complimentary DNA (deoxyribonucleic acid) probes are done.
  • In the case of rabies, serological tests for antibodies would confirm the diagnosis.
  • For influenza, ELISA test or immunofluorescence will differentiate the strains of the virus and confirm the diagnosis.
    In bunyavirus infections ELISAs are used to detect and distinguish the viral antigens.

So, the most common tests are

  1. ELISAs (Enzyme linked immunosorbent assay)
  2. Agglutination
  3. Immunoassay
  4. Immunofluorescence
  5. Polymerase chain reaction

Microbiology with Diseases by Taxonomy Chapter 25 Answers 10MC

  • Ebola virus causes uncontrolled bleeding from the eyes, nose, mouth, ears, and anus. Ebola viruses belong to the family filovirdae. The initial method of transmission is not known. Fruit bats seem to be natural reservoirs of ebola viruses. The main clinical manifestation of this disease is internal bleeding under the skin and bleeding from all the openings of the body. The internal organs get reduced into a jelly-like substance. The reason behind the hemorrhage is the infected cells lining the blood vessels get affected by the virally coded glycoprotein. It prevents cells from adhering to one another and causes blood to leak out of the vessels. Almost 90% of the patients die. Hence, the option (a) is correct.
  • Bunyavirus does not cause these symptoms. Most of these viruses are zoonotic pathogens. The four genera of the family bunyaviridae have human pathogens. Hemorrhagic fever, Rift valley fever, California encephalitis are some of the diseases produced by bunyaviruses. Each bunyavirus have their target. Some of the diseases are indistinguishable from diseases produced by other viruses. Hence lab tests are necessary for diagnosis. Hence, the option (b) is not correct.
  • Hantavirus does not cause bleeding from eyes, nose, mouth, ears and anus. Humans get affected by Hantaviruses by contact with rodent excreta or saliva. Hantavirus hemorrhagic fever with renal syndrome (HFRS) and Hantavirus pulmonary syndrome (HPS) can be fatal. HFRS in later stages can cause vascular leakage. Hence, the option (c) is not correct.
  • Human immunodeficiency virus does not cause bleeding. It is the progressive decline in the immune system allowing dangerous infections and cancers. It affects the helper T cells, macrophages and dendritic cells of immune system. Hence, the option (d) is not correct. Hence, the correct option is (a) Ebola virus.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 10SA
The West Nile virus is an arbovirus belonging to the family flaviviridae. It is endemic to Israel and Africa.
The virus is carried by the infected migratory birds across the lower states of US. Mosquitoes spread this viral infection among the birds, birds to horses; and birds to humans. This virus cannot produce significant viremia in humans and thus human is dead-end host for this virus.
In subtropical and temperate areas, the West Nile Encephalitis occurs in summer. In tropical areas the incidence of infection is greater in the rainy season due to the abundance of mosquitoes.
The West Nile virus became evident in US in summer 1999 in New York City. The epidemic occurred during extreme dry summers in urban SLE. The environmental conditions that are favorable for the amplification of this virus and transmission by hosts may be summer. That may be the cause that cases of West Nile Encephalitis is more in summer than in winter.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 11MC

  • Reoviruses such as rotaviruses and coltiviruses are unique in having double-stranded RNA (ribonucleic acid). Reoviruses are the only microbes whether viral or cellular have double-stranded RNA in their genome. Every virus has 10-12 segments of double-stranded RNA. They are also called orphan viruses. They got the name reo as an acronym from ‘respiratory, enteric, orphan’. Hence, the option (b) is correct choice.
  • Option (a) states that they are all naked, this is not correct. There are so many families who are naked without envelop. Families like Picornviridae, Calciviridae, Astroviridae, and Hepeviridae all of them are naked viruses. So, this is not the unique feature of reoviruses.
  • Option (c) states that both the viruses are arboviruses and zoonotic. This option is not correct. Rotaviruses are transmitted by fecal-oral route. This is not an arbovirus. Coltivirus is an arbovirus and causes zoonosis called Colorado tick fever, as it is transmitted by tick bites.
  • Option (d) states that both the viruses are having protein spikes. This option is not correct. Only rotavirus has spikes of glycoprotein on their capsids. They act as attachment molecule and thereby induce endocystosis. So, this is not the unique feature of both rotaviruses and coltiviruses. Hence, rotaviruses and coltiviruses are having double-stranded RNA, which is a unique feature. Hence, the correct option is (b) having double-stranded RNA.

Microbiology with Diseases by Taxonomy Chapter 25 Answers 11SA

  1. The 1918-1919 pandemic influenza viruses were the first one of the two influenza viruses. The second one of the influenza virus is A 2009 (H1N1). Both the types have many genetic sequences in common. The emergence of new strains like H1N1 viruses results in outbreaks internationally.
  2. 1918 pandemic killed young, healthy adults. It is called Spanish influenza. This virus kills through the over immune reactions of the body’s immune system. As the young people had strong immune system, thus kills the body. The weak individuals and children with weak immune system had fewer deaths.
  3. In Spanish influenza infection was only in the respiratory system. The cause of death was bacterial pneumonia and viral pneumonia. The genomic sequences of this virus were like an avian like H1N1virus. It did not have multibasic HA cleavage site, which shows that it is a highly pathogenic avian influenza virus.
  4. The 2009 H1N1 pandemic strain resulted from genetic reassortment of four influenza A viruses. The infection started in a Mexican town in February. In April, there were number of influenza like cases. There was human to human transmission. This made the WHO (World Health Organization) to elevate the pandemic alert.
  5. By May 21st, forty one countries reported cases of influenza. The genetic component of this 2009 H1N1 pandemic strain resulted from reassortment of H3N2 North American and H1N2 swine viruses. This was seen in pigs since 1997 and developed adaptation in pigs.

Microbiology with Diseases by Taxonomy Chapter 24 Answers

Microbiology with Diseases by Taxonomy Chapter 24 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 24 Answers 1CM
The herpes viruses are belongs, to the family Herpesvirdae. Many viruses belongs to this family are infective to the humans. Among them are herpes simplex, varicella-zoster, and Epstein-Barr viruses are infecting 90% of the adults in US. The concept map of herpes simplex virus is as follows.
microbiology-with-diseases-by-taxonomy-chapter-24-answers-1cm

Microbiology with Diseases by Taxonomy Chapter 24 Answers 1CT
The replication of poxvirus occurs in the cytoplasm of the infected cell. This is a unique feature. The problem is that the cytoplasm does not contain DNA. The DNA is present only in the nucleus of the host cell.
In the case of poxvirus, DNA replication takes place in virosomes. Virosomes are the regions in the cytoplasm of the infected cell, and it does not have any cellular organelles. These virosomes are foci of DNA replication and morphogenesis of poxvirus.
Then secondary uncoating takes place and viral genomes are released into the cytoplasm of the infected cell. This process brings the DNA template and replication proteins, which are newly synthesized into contact.
As the poxvirus is large, replication is quick, and takes almost 12 hours. Then the infected cell dies due to the release of viruses.
For genome transcription, poxvirus encodes its own machinery. The machinery includes DNA dependent RNA polymerase and other activating, modulating proteins extra. Hence, replication in cytoplasm is possible for poxvirus.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 1L
The stages of lesion in poxvirus infection:

  1. The poxviruses produce lesions in a series of stages.
  2. The lesions are flat and red. This is macular stage.
  3. The lesions are raised sores. This is popular stage.
  4. The lesions are filled with clear liquid. This is vesicular stage.
  5. The clear fluid changes into pus and is called pustular stage.
  6. Pustules dry up and form crust.
  7. As the dermis is penetrated by the lesions scar is formed.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 1M

  1. The disease, chicken fox is caused by the virus, varicella- zoster. This virus belongs to the family Herpesviridae. This disease is transmitted, through the air hence; it is called air borne disease. Thus, the matching answer is (B) Herpesviridae.
  2. The disease, Smallpox is caused by variola virus. This virus is belongs to the family Poxviridae. The variola virus is existed in two forms; they are variola major and variola minor. It is a very infectious disease affects the skin, blood vessels and respiratory mucosa extra. Thus, the correct matching answer is (A) Poxviridae.
  3. The disease, Cowpox is caused by poxvirus. This virus is belongs to the family Poxviridae. The cows are affected by this disease; sometimes, this may leads to death of cow. Thus, the correct matching answer is (A) Poxviridae.
  4. The disease, Molluscum contageosum is caused by Molluscipoxvirus. This virus belongs to the family Poxviridae. It is a human specific pox disease, often associated with acquired immuno deficiency syndrome (AIDS). Thus, the correct matching answer is (A) Poxviridae.
  5. The disease, Human herpesvirus 1 (HHV-1) infection is caused by Human herpesvirus 1 (HHV-1) virus. This virus belongs to the Herpesvirdae family. This disease, is also called oral herpes, it mainly affects the lips and forms itchy skin lesions. Thus, the correct matching answer is (B) Herpesvirdae.
  6. The disease, Whitlow is caused by HHV-1 or HHV-2 virus. This virus belongs to the family Herpesviridae. Thus the correct matching is (B) Herpesviridae.
  7. The disease, Shingles is caused by varicella-zoster virus. It belongs, to the family Herpesviridae. Thus the correct matching is (B) Herpesviridae.
  8. The disease, Burkett’s lymphoma is caused by Epstein – Barr virus. It is belongs, to the Herpesviridae family. Thus the correct matching is (B) Herpesviridae.
  9. The Infectious mononucleus is caused by Epstein – Barr virus. It is belongs, to the family Herpesviridae. Thus the correct matching is (B) Herpesviridae.
  10. The disease, chronic fatigue syndrome is caused by Epstein – Barr virus. It is belongs, to the family Herpesviridae. Thus the correct matching is (B) Herpesviridae.
  11. The disease, Cytomegalovirus infection is caused by Cytomegalovirus. It is belongs, to the family Herpesviridae. Thus the correct matching is (B) Herpesviridae.
  12. The disease, Genital warts is caused by papillomavirus. It is belongs, to the family Papillomaviridae. Thus, the correct answer is (C) Papillomaviridae.
  13. The disease, Roseola is caused by Human herpesviurs-6. It belongs, to the family Herpesviridae. Thus the correct matching is (C) Herpesviridae.
  14. The disease, plantar warts is caused by papillomavirus. It is belongs, to the family Papillomaviridae. Thus, the correct answer is (C) Papillomaviridae.
  15. The disease, Progressive multifocal leukoencephalopathy is caused by latent infections of JC virus it belongs, to the family Polymaviridae. Thus, the correct matching is (G) Polymaviridae.
  16. The disease, Common cold is caused by adenovirus. It is belongs, to the family Adenoviridae. Thus, the correct answer is (D) Adenoviridae.
  17. The disease, Hepatitis B is caused by Hepatitis B virus. It is belongs, to the family Hepadnaviridae. Thus, the correct matching is (E) Hepadnaviridae.
  18. The disease, Fifth disease is caused by B19 virus. It belongs, to the family Parvoviridae family. Thus, the correct matching is (F) Parvoviridae.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 1MC
DNA (deoxyribonucleic acid) virus in Poxviridae is relatively large and well suited potentially for vaccinations and introduction of genetic material in gene therapy. This virion is very large. It is of the size of 200 nm in diameter and 300 nm in length. The shape is usually like a rounded brick wrapped around by endoplasmic reticulum (ER). The entire genome is a linear, double stranded DNA segment.

  • The vaccinia virus of this family is the active agent in the small pox eradication. Also, it is used effectively for foreign protein expression. It shows a strong host immune response. Hence, the correct option (b).
  • Herpesviridae is a large family of DNA viruses. The viruses which belong to this family are called herpesviruses. Some of these viruses like Varicella Zoster virus, Epstein – Barr virus, cytomegalovirus, HSV-1, and HSV-2 are widespread among humans. Herpes viruses are large double stranded linear DNA genomes. They are not suited for vaccinations and gene therapy. Hence, the option (a) is not correct.
  • Papillomaviridae is family which has non-enveloped DNA virus. They cause small papillomas. This is not a large sized virus. A single viral protein is called L1 form a capsid of 55-60 nm. Prophylactic HPV vaccines are designed with L1 protein, which is successful. Hence, the option (c) is not correct.
  • Hepadnaviridae: This family consists of viruses, which are enveloped. The genomes are very small and partially double stranded and partially single stranded. These viruses cause liver infections. Hepatitis B Virus is the member of this family. It is not a potential virus for vaccinations. Hence, the option (d) is not correct.
  • So, the poxviridae family viruses are relatively large and well suited for vaccinations and in gene therapy. Hence, the correct answer is option (b) Poxviridae.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 1SA
Smith family gets fever blisters regularly. It shows that they are infected with herpes virus. Infection takes place when the herpes virus enters the mucous membranes of lips, genital region, or through the cut on the skin. In these cases it produces oral herpes, genital herpes, and whitlow respectively.
This virus can remain dormant, for some years. In trigeminal ganglia, brachial ganglia or sacral ganglia the virus can reside in the body for several years and get activated due to stress or age, or due to immunosuppression and cause oral herpes, genital herpes and whitlow.
This recurrence is the distressing feature of this disease. Almost 2/3 of patients will experience recurrence of lesions.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 2CT
The young patient had rosy facial rash and coldlike sniffles. The Duration of the symptom was two weeks. The diagnosis of the disease, most likely may be Roseola.
The main causative organism of Roseola is Human herpes virus 6. It belongs, to the Genus is Roseolavirius.
The common symptoms of this disease are sudden fever, sore throat; enlarged lymph nodes, and rosy rash on the face; neck, trunk and thighs.
This disease got its name due to their ‘rose colored rashes.’ Thus, Rene’s sulfuring due to Roseola disease, for past two weeks.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 2MC

  • Most animal poxviruses are unable to infect humans because its attachment to human cells is unlikely. They are specific to the species. Their surface proteins are different. Some of the animal poxviruses like that of monkeys and sheep can infect some humans, because they have surface antigens similar to that of those animals. Hence, the option (c) is correct.
  • The option (a) says that affected animals are not in frequent contact with humans. This is not correct. Even if those animals are in contact with humans the poxvirus cannot attach itself to the humans as their surface protein is different. Hence, the option (a) is not correct.
  • The option (b) says that the human immune system makes it impossible for the foreign viral particles to reproduce effectively. This is not correct, because the attachment of the viral protein with that of human itself is not possible. So, the virus cannot enter the immune system of human. So, the option (b) is not correct.
  • The option (d) says that human cells lack the necessary enzyme for infection. Enzymes are used as a catalyst for any reaction. But in this case there is no attachment between the proteins and so there is any need for any enzymes to react. Hence, the option (d) is not correct.
  • Therefore, most animal poxviruses cannot get attached to the humans, as their surface antigens are different. Hence, the correct answer is option (c) Attachment to human cell is unlikely.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 2SA
Stocks of smallpox viruses are kept in laboratories in US and Russia. It is a research tool for investigations.
The governing body of the World Health Organization (WHO) has decided to keep the two vials of this deadly virus. They have limited any new research, with this virus till they take the next decision in 2014.
The two vials one in Georgia and one in Siberia. The Russian facility has survived several stays of execution as scientists had argument over it. So, as they have limited the research on this virus, one cannot do so till the 64th, World Health Assembly.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 3CT
Certain features of smallpox that allowed them to be eradicated are that it is visible and can be spotted out very easily. The interval between the time of exposure and the onset of symptoms are very short.
The second feature is that it does not have animal reservoirs only humans can transmit the disease.
People who were affected developed lifelong immunity to this disease. The vaccines are highly effective. So, large number of people could be vaccinated by trained vaccinators of World Health Organization.
Hepatitis B is also a suitable candidate for eradication. Hepatitis B virus is a human pathogen. It does not have any animal reservoirs. The Hepatitis B vaccine is available and it is very effective. Hepatitis B is common in many countries. Children who are infected with this disease in their infancy suffer chronically and they excrete the virus recurrently and persistently.
The biological features, which make the disease suitable for eradication, are as follows:

  • First one is effective intervention that is good and effective vaccination should be available to stop the transmission of the disease.
  • The second one is that tools for diagnosis of the disease should be specific and sensitive, so that different levels of transmission can be detected.
  • The third one is human should be in the live-cycle of the agent and there should not be any animal reservoir.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 3MC

  • Papules are not the initial stage of lesions caused by poxvirus. Papules are second stage and it is characterized by raised sores. Hence, the option (b) is not correct.
  • Pustules are not the initial stage of lesions caused by poxvirus. Papules are pus filled lesions. Hence, the option (c) is not correct.
  • Pocks are not the initial stage of lesions of poxvirus. Pocks are also known as pustules or pox, which is pus filled lesions. Hence, the option (d) is not correct.
  • The poxvirus causes lesions, which have different stages. The initial stage lesions are called macules. They are flat and red skin lesions. Hence, the correct answer is option (a) macules.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 3SA
The Variola major causes severe disease with 20% or higher mortality rate. The Variola minor causes less severe disease with 1% mortality rate. This infection is also called cotton pox, alastrim and Cuban itch.
The symptoms like high grade fever (1070F), weakness and delirium are more debilitating in the case of Variola major. People cannot be ambulant.
In Variola minor there will be high grade fever, general weakness. But it is not as debilitating like Variola major. Patients are ambulant and due to this they may be infecting more people.
The long term effect of Variola major is severe scars on the face. The less common effects are osteomyelitis, arthritis, which causes limb deformities and blindness due to corneal ulceration and scarring. The effects of Variola minor are that they also leave scars in the skin especially on the face.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 4CT
Infection with double-stranded DNA (deoxyribonucleic acid) virus causes the symptoms. These viruses produce symptoms that of common cold.
They spread through respiratory droplets and also through drinking water, which is not chlorinated. These adenoviruses are very stable outside the body of the host and live in fomites.
The manifestations of these viruses are fever, sore throat, headache, cough, and general weakness.
Here in this case, the common source of infection may be drinking water or the water in the swimming pool, which is not properly chlorinated.
The camp management should properly chlorinate the drinking water and also the swimming pool to limit such an outbreak in future.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 4MC
The virus Variola major affects internal organs before it appears on the skin- it is a true statement.
The incubation period of this virus is 12 days. As soon as it is inhaled, it enters the oropharyngeal mucosa and enters the lymph nodes. Here, they multiply and move to other cells. There, lysis of the infected cells occurs and the virus is found in the blood stream.
The second stage in the multiplication of this virus occurs in spleen, and bone marrow. The symptoms are fever, muscle pain, and headache. There may be nausea and vomiting as the digestive system is also affected. This is called pre-eruptive stage.

  • After 12-15 days, lesions show up as small reddish spots in the mucosa of mouth, palates, and tongue. Skin rash appear one or two days after the lesions of mucous membrane. Macules appear first and progresses to the other stages. Hence the option (b) is correct.
  • The option (a) says that Variola major has less than 1% mortality. This is not correct. The mortality rate is 30-35%.
  • The option (c) states that Variola major has been totally eradicated from the earth. Smallpox is eradicated globally. In 1980, the WHO (world health organization) declared the eradication of smallpox globally. But stocks of this virus are still kept in labs in US and Russia. Hence, the option (c) is not correct.
  • The option (d) states that skin lesions caused by it are smooth, waxy, tumor like nodules on the face. This is not true. Skin lesions progress from macules to papules to vesicles and then to pus filled pustules. They are raised, round and tense, and firm lesions, which form crusts after two weeks. So, Variola major affects the internal organs before appearing on the skin.
  • Hence, the correct option is (b) it affects the internal organs before appearing on the skin.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 4SA
The observation that led the scientists to find the relationship between chickenpox and shingles is that Varicella-Zoster Virus. The lesions of shingles can cause chickenpox in persons, who have not had chickenpox. The Varicella Zoster Virus causes both shingles and chickenpox.
Shingles occur once or twice in a person’s life after the age of 45, unlike Herpes simplex infections which occur frequently. Before, making chickenpox vaccination as a routine vaccination in children, many children used to be affected by chickenpox and there used to be few cases of shingles.
From this, it was understood that children who develop chickenpox, develop complete immunity to Varicella Zoster Virus. They will not develop shingles in later life.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 5CT
A week after the vacation all the members of the family developed cold sores. The other names for cold sores are oral herpes and fever blisters. This infection is caused by Herpes simplex virus – Human herpes virus1. The period between the time of infection and manifestation of the disease is around two weeks.
Herpes infection is a viral infection and it is contagious. This is transmitted by close contact like kissing an infected person in that affected area. This can also be transmitted by oral sex. So, it is not a sexually transmitted disease altogether. The young children could have got that infection by kissing or by close contact.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 5MC

  • Cytomegalovirus in fetuses would be potentially most serious herpes virus. Transmission of this virus occurs through sexual intercourse and also from in-utero exposure, vaginal delivery, and so on. Fetuses are susceptible to severe complications of this virus. This is also called teratogenic, because it causes birth defects. When this virus attacks the stem cells in an embryo or fetus, mental retardation, visual and hearing loss, or death may result. Hence, the correct option is (d).
  • A whitlow is an inflamed blister. It occurs when HHV-1 or HHV-2 enter a cut in the skin of the finger. It is dangerous for the children who suck their thumbs. Health workers in gynecology, obstetrics, and dentistry should wear gloves when treating patients with herpes lesions. This is a potential source of infection, but not serious as cytomegalovirus in fetuses. Hence, the option (a) is not correct.
  • Ocular herpes is caused by latent herpes virus HHV-1, which affects the ophthalmic branch of the trigeminal nerve. Recurrent infection can cause corneal damage and blindness. It is not as serious as cytomegalovirus in fetus. Hence, the option (b) is not the correct option.
  • Shingles is called herpes zoster. It is caused by Varicella-Zoster Virus. This virus remains dormant for years. In some patients who were previously affected by chicken pox, certain conditions like stress, immune suppression, and aging reactivate the virus. These viruses travel down the nerve they occupy and produce skin rashes in the distal end of the nerves, which is very painful. This viral infection is not potentially serious. Hence, the option (c) is not correct.
  • So, cytomegalovirus in fetus is most potentially serious than all the other options. Hence, the correct option is (d) cytomegalovirus in fetuses.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 5SA
In countries with poor sanitation, low level of hygiene and less medical facilities, infection with Epstein-Barr (EBV) virus occurs in childhood. These infections are mostly asymptomatic because, the child has immature cellular immune system. Immature immune system cannot cause severe damage to the tissues.
In developed countries where living conditions are good and medical facilities are available, infection in the childhood does not happen rather it is in the adolescence. So, infection in later life results in severe cellular immune response and cause mononucleosis and other diseases.
In fact, cofactors also play a role in the development of diseases. In the case of Burkett’s lymphoma by Epstein – Barr virus, the infection is limited to young men who were exposed to malaria parasite. In nasopharyngeal cancer, certain cofactors in the food, genes in particular population and environment are involved.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 6MC

  • A man infected with adenovirus will exhibit symptoms of common cold. It includes fever, headache, cough, and pinkeye. This virus is spread by droplets and is stable outside the body. When the cells lining the respiratory tract are affected by the adenovirus respiratory symptoms are manifested. If adenovirus affects the conjunctiva, it causes pinkeye. Hence, the correct option is (e) which includes all the symptoms.
  • Option (a) states that the only fever is the sign and symptom of adenovirus, whereas these viruses cause fever, head ache, cough, and pinkeye. Hence, the option (a) is not correct.
  • Option (b) is not correct because headache is not the only symptom that is exhibited by adenovirus. Option (c) is not correct because cough is not the only symptom of adenovirus.
  • Option (d) is not correct because pinkeye is not the only symptom exhibited by a person infected with adenovirus.
  • So, all the symptoms mentioned in the options (a), (b), (c), and (d) will be exhibited by that infected person. Hence, the correct answer is option (e) all of the above.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 7MC

  • The inflammatory condition of the liver is called hepatitis. Hepatitis B virus causes infection in the liver. It is the only DNA (deoxyribonucleic acid) virus, which causes hepatitis. Hence, the option (d) is correct.
  • The option (a) is not correct. Fifth disease is also called erythema infectiosum. It is caused by parvovirus. The clinical symptoms are fever, headache, stuffy nose, and facial redness.
  • The option (b) is not correct. PML is progressive multifocal leukoencephalopathy caused by polyomavirus called JC (John Cunningham) virus in cases of immunodeficiency. This virus causes brain damage, which is irreversible.
  • The option (c) is not correct. Seed warts are caused by papillomaviruses. Papillomas found on toes or fingers are called seed warts. So, hepatitis is the inflammation of the liver. Hence, the correct option is (d) hepatitis.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 8MC

  • In children, Parvovirus infections are accompanied by high mortality rate is a false statement. Parvovirus is with single strand DNA (deoxyribonucleic acid) and it is the only pathogen, which affects humans. In children, fifth disease is caused by B19 virus, which is characterized by redness of skin, from the cheek and arms, thighs, and trunk. This is harmless. Hence, the correct option is (c).
  • B19 virus is the primary Parvovirus of humans. The statement is true. This virus belongs to genus Erythrovirus, which causes the fifth disease of erythema infectiosum. Hence, the option (a) is not correct.
  • Erythema infectiosum is caused by a Parvovirus is a true statement. The primary Parvovirus B19 virus in the genus Erythrovirus causes this disease. Hence, the option (b) is incorrect.
  • Parvovirus infection in humans’ results in infectious reddening of the skin is a true statement. This reddening of the skin starts from the cheeks. Later on, it appears on the thighs, buttocks, arms, and trunk. The rashes, which are caused by this virus, are very distinctive, so that it can be diagnosed by appearance. Hence, the option (d) is incorrect. In children, Parvovirus does not produce any harmful disease.
  • Hence, the correct option is (c) in children, parvovirus infections are accompanied by a high mortality rate.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 9MC

  • The distinguishing feature of poxvirus is its large size. The diameter is about 200 nm and the length is about 300 nm. These poxviruses are potential vectors for introducing the genetic materials in vaccinations and gene therapy due to its large size. Hence, the correct option is (a).
  • The poxvirus is not a polyhedral capsid. The virons are enveloped and look like a brick in shape or as a rounded brick in an oval shape. The shape varies according to the species. It is a double stranded DNA (deoxyribonucleic acid) with complex capsids and envelops. Hence, the option (b) is not correct.
  • The poxviruses are double stranded DNA viruses. They are with complex capsids and envelopes. So, it is not distinguished with the type of RNA (ribonucleic acid) it contains. Hence, the option (c) is not correct.
  • The diseases caused by poxvirus in humans are smallpox and molluscum contagiosum. In animals, it causes orf, cowpox, and monkeypox. It does not produce several types of warts. Hence, the option (d) is not correct.
  • So, the distinct feature of poxvirus is its large size. Hence, the correct answer is option (a) its large size.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 10MC

  • To prevent further risk of monkeypox infection in Zaire, we have to reinstate smallpox vaccinations for the populations of Zaire. Some scientists say that cessation of smallpox vaccinations may have increased the susceptibility to monkey pox, as smallpox vaccination also is a protection against monkey pox. So, they feel that smallpox vaccination should be reinstated in Zaire. Hence, the option (c) is correct.
  • Option (a) states to catch the monkeys for inoculation with monkeypox vaccine and then release them. Monkeypox is a disease not of monkeys, but of rodents and prairie dogs. Hence, option (a) is not correct.
  • Option (b) is incorrect because the virus does not infect only local tissues, but systems and internal organs are also affected by this infection. Moreover, it is not the possible and right way of eradication.
  • Option (d) is incorrect, because humans also get monkeypox by close contact with infected animals. In the past decade, there is increase in the number of persons infected with monkeypox. The reason may be a change in the viral antigen or human encroachment into monkey habitats,
  • Hence, the correct option is (c) Reinstate smallpox vaccinations for the population of Zaire.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 11MC

  • Herpesviridae family has viruses that exist in latent state in humans often. For years, they remain inactive inside the infected cells. They may get reactivated due to some factors like oldage, chemotherapy, stressful conditions, and immunosuppression. Some of this latent viruses gain entry into the chromosomes causing genetic changes and even cancers. Hence, the option (a) is correct.
  • Poxviridae family viruses do not show any latent stage of infection. Hence, option (b) is incorrect.
  • Viruses belonging to Adenoviridae family do not show this latency. Adenoviruses are one of the many causes for common cold. It is stable outside the body and survives in water, which is not properly chlorinated. Hence, the option (c) is not correct.
  • Parvoviridae family viruses are small in size and cause diseases, which are endemic in animals. In humans, it causes fifth disease, which is harmless. This virus does not exist in latent state in humans. Hence, the option (d) is not correct.
  • Herpesviridae viruses mostly exist in latent state in humans. Therefore, the correct option is (a) Herpesviridae.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 12MC

  • Outside the host’s body, if the envelop of a virus is unstable it would be transmitted by intimate contact. For example, poxvirus has unstable envelope outside a host’s body and it is necessary to have close contact to get infected. Hence, the option (b) is correct.
  • Option (a) states that the virus would be a dsRNA (double stranded ribonucleic acid) virus. This is a group of viruses, which have diversity. One example is Rotavirus; it dsRNA, but no envelope. So, this option is not correct.
  • Option (c) states that touching a doorknob would easily transmit it. This is not correct. By inhalation of droplets or by dried crusts, the virus can be transmitted. This infection spreads by close contact, but not by just touching a doorknob.
  • Option (d) states that the virus would eventually cease to be a threat to the population. This is not correct. As this virus spreads by close contact by inhalation or by crests, once it enters the host this becomes stable. So, virus with unstable envelope outside the host needs intimate contact to be transmitted.
  • Hence, the correct option is (b) it would be transmitted by intimate contact.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 13MC

  • Being habitually careful not to touch or rub eyes with unwashed hands would reduce the risk of contracting common cold. One of the causes of common cold is Adenovirus. This virus is stable outside the host and can survive in fomites and drinking water, which is not properly chlorinated. This virus spreads by respiratory droplets. Some adenoviruses cause pinkeye. Hence, the option (d) is correct.
  • Chickenpox is caused by Varicella zoster virus. This spreads by droplet infection by sneezing, coughing, and also by direct contact with the secretions from lesions. So, option (a) is incorrect.
  • Infectious mononucleosis is caused by Epstein-Barr virus. It is transmitted through saliva by sharing drinking glasses and by kissing. Initially it infects epithelial cells of pharynx and parotid salivary gland. Then it enters the blood circulations causing viremia. Hence, the option (b) is not correct.
  • Seed warts are caused by Papilloma virus. These are benign growth of epithelium of the skin. Papillomas found on the fingers or toes are called seed warts. It is transmitted by direct contact. As this virus is stable outside, it can spread through fomites. In the same person, it can spread form one part of the body to the other part by autoinoculation. Hence, the option (c) is not correct.
  • Cold spreads mainly by touching or rubbing eyes with unwashed contaminated hands. Hence, the correct option is (d) a cold.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 14MC
Human herpesvirus 2 can cause genital herpes, and infect baby at birth and causes above 10% of cold sores. This is contagious and causes most genital herpes. This virus spreads by sexual intercourse. This virus resides in the sacral ganglion and becomes latent.

  • When viral reactivation occurs it replicates and produces new lesions. It is seen in external genitalia, buttocks, and anus. 10% of oral herpes is due to HHV-2. 70% of the neonatal herpes is due to this virus. Hence, the option (d) is correct.
  • Option (a) states that human herpes virus-2 (HHV-2) can cause genital herpes. It is transmitted during child birth and it is cause for 70% of neonatal herpes. It produces cold sores also. Hence, the option (a) is not correct.
  • Option (b) states that this virus may infect a baby at birth; the baby is infected at birth when it comes in contact with these lesions in the birth canal. Neonatal infections are serious, causing 80% of mortality if the virus affects the central nervous system. If it is oral or only skin lesions, the mortality rate is 30%. This is not the only manifestation of this virus. So, the option (b) is incorrect.
  • Option (c) states that HHV-2 causes 10% of cold sores; these are itchy, painful skin lesions, which occur on the lips. The presence of HHV-2 in the oral lesions and HHV-1 in the genital area may result due to oral sex. In severe infections, lesions go down to the oral cavity. This is not the only manifestation of this virus. Hence, this option is not correct.
  • So, Human herpes virus 2 causes genital herpes, infect a baby at birth, causes 10% of cold sores. Hence, the correct option is (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 24 Answers 15MC

  • Herpesvirus is latent and can reactivate to cause further disease. They stay inactive inside the infected cells even for years. It can be reactivated by old age, stressful conditions, chemotherapy, and immune-suppression. Sometimes, this virus may enter into the chromosomes and cause genetic changes also. Hence, the option (a) is correct.
  • Papillomavirus is not latent. It causes papillomas on the skin or mucous membrane. It is also called warts. Seed warts, flat warts, genital warts are some of the types of warts caused by this virus. Hence, option (b) is not correct.
  • Adenovirus is not latent. This is one of the causes of common cold. It is transmitted by respiratory droplets and through drinking water, which is not properly chlorinated. Hence, option (c) is not correct.
  • Parvovirus is not latent. It is the only single stranded DNA, which infects humans. It is small in size. It causes many endemic diseases in animals. In humans, it causes fifth disease or erythema infectiosum. Hence, the option (d) is not correct.
  • Herpesvirus is latent and gets reactivated by factors like old age, stressful conditions, and immune-suppression. Hence, the correct option is (a) Herpesvirus.

Microbiology with Diseases by Taxonomy Chapter 23 Answers

Microbiology with Diseases by Taxonomy Chapter 23 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 23 Answers 1CM
The intestinal protozoan parasites are divided into four groups. They are ciliates, amoebae, the flagellates, and apicomplexans. The classification is clinically useful. It groups the parasites based primarily on the mode of locomotion.
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Microbiology with Diseases by Taxonomy Chapter 23 Answers 1CT
In the case of Entamoeba, 10% of the world’s population carries this parasite asymptomatically in the gastrointestinal tract. Once the disease develops, the annual mortality goes upto 100,000. In less developed countries, carriers are predominant. Infections with Acanthamoeba and Naegleria are rare compared to Entamoeba. So, Entamoeba infection is threat to more people in regard to incidence.
The clinical manifestation of Entamoeba is luminal amoebiasis, which is less severe invasive amebic dysentery. It is more serious and affects 500 million people worldwide and is the most serious invasive extra-intestinal amebiasis. Without adequate treatment the later two manifestations may be fatal.
In the case of Acanthamoeba, the amebic encephalitis caused is fatal. The manifestations are headache, altered mental state and neurological disorders. Symptoms worsen over a period of week till the patient dies. Physicians treat this disease with pentamidine. So, patient has few weeks to be diagnosed and treated.
In the case of Naegleria, the trophozoites enter the brain and cause amebic meningoencephalitis. The symptoms are severe headache, vomiting, fever, destruction of nervous tissue, brain hemorrhage leading to coma. Physicians treat the disease with amphotericin. After the onset of symptoms, the patient dies within three to seven days. By the time the disease is diagnosed, patient dies. So, Naegleria infection is the most serious one.
The answer is not same for both questions, because even if the incidence is high in the case of Entamoeba, it can be diagnosed and treated, so that the life is saved. In the case of Acanthamoeba, after the onset of symptoms, the patient has few weeks to be diagnosed and treated.
But, in the case of Naegleria the patient dies within three days to seven days after the onset of symptoms. So, there is very little chance or no chance of saving the life of the person infected with Naegleria. Hence, the mortality rate is almost 100% in this case.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 1FB
Balantidium coli can be distinguished from Entamoeba histolytica microscopically because B. coli have cilia.
Balantidium coli belong to ciliate protozoan species, whereas Entamoeba histolytica, also a parasitic protozoan, belongs to Amoebae.
Ciliates are protozoan parasites with cilia. The trophozoites use cilia for locomotion and for acquiring food. Balantidium is a large ciliate and is the only ciliate pathogenic to humans. Humans are infected by ingestion of cysts with contaminated food and water. In the small intestine, encystment occurs and the trophozoites are released. They have cilia with which it attaches itself to the intestine and also burrow through the intestinal mucosa.
Entamoeba move and acquire food with pseudopodia and is the most important pathogenic amoeba.
Hence, the correct answer is cilia.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 1L
The plasmodium life cycle has three stages. They are exo-erythrocytic phase, erythrocytic cycle, and sporogonic phase. The given diagram is labeled as follows:
microbiology-with-diseases-by-taxonomy-chapter-23-answers-1l
The life cycle of Plasmodium has three stages. They are as follows:
1. Exo-erythrocytic phase –
The forms of the parasite involved are sporozoites and merozoites. Sporozoites are injected into the human by Anopheles mosquito. They enter the liver cells through the blood circulation. Schizogony occurs in liver cells and merozoites are formed.
2. Erythrocytic cycle –
The forms of the parasite involved in this cycle are merozoites, trophozoites and male and female gametocytes. Merozoites in the blood circulation enter the erythrocytes and change into trophozoites. Trophozoites undergo schizogony and produce more merozoites. These merozoites lyse the erythrocytes and enter the blood circulation. Some of the merozoites stay in the erythrocytes and form male and female gametocytes.
3. Sporogonic phase –
The forms of the parasite in this cycle are gametocytes, oocyst, and sporozoites. The gametocytes in the erythrocytes are ingested by mosquitoes. In the digestive tract of mosquitoes the gametocytes are freed. The fertilization takes place and zygotes are formed. The zygote becomes an ookinete, which becomes an oocyst. After meiosis, oocyst ruptures and sporozoites are formed. Thousands of sporozoites migrate into the salivary glands of the mosquito, which in turn is injected into a new host.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 1M
The term “Balantidium coli” matches with option (G) trophozoites.
This ciliate protozoan infects the humans. It causes balantidiasis. It is transmitted through feco-oral route. This parasite has two developmental stages. One is trophozoite stage and the other is cyst stage.
The trophozoite has two nuclei. This macronucleoi is sausage shaped and long and the micronucleus is situated next to it and is hidden by it. It has a pointed end anteriorly and an opening called peristome is situated at this end. This leads to the mouth called cytosome.
The infection is caused by the ingestion of cyst. As soon as it reaches the small intestine, trophozoites are produced. In the large intestine, the trophozoites colonize and feed on intestinal flora.
Some of the trophozoites live in lumen of the intestine and get disintegrated and encysted. Some of them penetrate the wall of the large intestine by proteolytic enzymes and are multiplied.
Hence, the term “Balantidium coli” matches with (G) trophozoites.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 1MC
Parasitology is the study of parasitic eukaryotes. It has two categories. One is protozoan parasites and the other is helminthic parasites. This is in the case of both humans and animals.
Parasites are organisms that live, grow, and feed on other host organisms. All the parasites have a definite host where as some have one or even more intermediate hosts.
Protozoan parasites are one-celled eukaryotic organisms. It includes amoebae and flagellates like Giradia. They could enter into an organism’s body intracellularly and extracellularly.
Helminthic parasites are multicellular worms. They enter the body extracellularly. Roundworms and flatworms are examples. Hence, the correct option is (d) Parasitic eukaryotes.
Parasitology is not the study of viruses. The study of viruses is called Virology and it is focused only on viruses. The viruses are parasitic particles, which infect the host cells and reproduce only inside the living cell. Hence, option (a) is not correct.
Parasitology is not the study of parasitic prokaryotes. Prokaryotes do not have a nucleus. Bacteria and archaea are prokaryotes. They can live in any environment. Some prokaryotes live as symbionts in the bodies or on the bodies of humans and other organisms. Hence, the option (b) is not correct.
Parasitology is not the study of parasitic fungi. The study of fungi is called mycology. Many fungi live as parasites on plants, animals and humans. Most of them are small in size. Some fungi live in soil, dead matter and on plants as symbionts. Hence, the option (c) is not correct.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 1MTF
The statement “Sexual contact is the most common method of transmitting parasites” is false.
Ingestion is the most common method of transmitting parasites.
For example, the cysts of the protozoan parasites are voided along with the feces. These cysts are ingested by contamination of water or food.
In the case of Entamoeba histolytica, Balantidium and Giaridia duodenalis the cysts voided along with feces is ingested.
Hence, the correct statement is “Ingestion is the most common method of transmitting parasites.”

Microbiology with Diseases by Taxonomy Chapter 23 Answers 1SA
Animal reservoir is the animal, which hosts the parasite and transmits by itself being immune to its effects. There are many animal reservoirs for many parasites, which affect humans. The zoonotic diseases are difficult to eradicate, as they are transmitted from animals.
Pigs are common animal reservoirs. They are asymptomatic. For example, the ciliate Balantidium coli occur when humans have close contact with pigs. The cysts of this parasite contaminate water sources.
As the animal reservoirs are asymptomatic, we cannot treat the animals nor can altogether eradicate the animals. For effective control of vector, precise sampling, showing the prevalence of the disease is needed.
The zoonotic diseases, which are vector borne act as bridge vectors transmitting the parasites to humans, to animals, and animals to humans. For example, leishmaniasis, babesiosis, and filariasis transmitted by vectors from animals are increasing. These infections affect domestic animals making them animal reservoirs. As the eradication of animals is rejected ethically, only the vectors should be controlled to eliminate such diseases.
The climatic change in the world causes alterations in the parasites’ transmission, which are transmitted by vectors. Hence, the animal reservoirs and insect vectors make it difficult to prevent or control the parasitic infections in humans.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 2CT
(a) Global warming can lead to the reemergence of malaria in the U.S. Malaria is endemic in tropic and sub tropic regions. This is the ideal climate for the mosquitoes to bread. Because of the global warming, the U.S also gets a climate like the tropics enhancing the breeding of mosquito vectors.
(b) Increased travel of individuals from endemic regions to U.S is a great risk for the reemergence of malaria, as they may be carriers of the disease. The movement of infected persons and mosquitoes from the endemic areas to U.S is a threat to reintroduce this disease in U.S.
(c) Increased immigration of individuals from endemic regions to U.S also lead to reappearance of malaria in U.S. Individuals form endemic areas may be carriers of this parasite. So, they will be spreading this parasite to the new host through the mosquito vectors.
(d) Regulations against the use of insecticides:
The insecticide DDT (Dichloro-diphenyl-trichloro-ethane) was used in the eradication of malaria. The mosquitoes developed resistance to DDT and it is an important factor in the reemergence of malaria. The effects of DDT on the environment and ecology, made us to abandon their use. Widespread use of insecticides can reduce mosquito breeding rates. As it is restricted there is reemergence of malaria.
(e) Laws protecting the wet lands:
The mosquitoes breed in wet lands. If there is drainage of wet lands and removal of standing water, there will be very much reduced production of mosquito vectors. As there are laws to protect the wet lands to maintain the ecology, the mosquitoes also breed and multiply.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 2FB
Toxoplasma gondii can be transmitted to humans from cat litter box.
This parasite is a protozoan and it causes toxoplasmosis. It infects the warm blooded animals. It is common in humans and asymptomatic in healthy individuals. In people with HIV (human immunodeficiency virus) and low immunity, this infection can be fatal. The ingestion of cysts by eating raw and uncooked meat, contamination of water and food with feces, is the root of infection.
Cats are the only hosts in which the parasite reproduces sexually. Cats get infected by eating a mouse infected with cysts. These cysts enter the gastro intestinal tract of the cat and infect the small intestine. Here the sexual reproduction takes place and oocysts are formed. Immature oocysts are shed along with cat feces.
Contact with infected cats and their feces is a great risk of infection. Cat can excrete ten million oocysts per day. These oocysts can live in moist soil for many months.
The oocysts are ingested by humans by contact with cat’s feces. Transplacental transfer of Toxoplama from the mother to the fetus in the first three months of pregnancy is very dangerous, as it causes congenital anomalies, or abortion, or still birth.
Hence, the correct answer is Toxoplasma gondii.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 2M
The term Echinococcus granulosus matches with (E) hydatid cyst.
This parasite is also called Hydatid worm or dog tape worm. This parasite lives in the small intestine of canids. Canids get this infection by the ingestion of cysticerci in herbivorus animals like cattle, sheep, and so on.
The intermediate hosts are sheep, cattle, and humans also. Humans get infected by ingestion of the eggs shed with dog’s feces. Inside the intestine, the larvae are released and these larvae enter the blood circulation and travel all over the body and form hydatid cysts in the body of the host. This is called hydatid disease.
These hydatid cysts get calcified over the years and get enlarged. They are filled with fluid and millions of protoscoleces. Every protoscolex can grow into a new worm. These hydatid cysts, if enlarged can cause tissue dysfunction. In the liver, it causes obstruction of bile ducts. If they are seen in heart, lungs, kidneys, and brain, that can be fatal.
When the cyst ruptures, millions of the protoscoleces spread throughout the body.
Diagnosis of this disease can be done by the visualization of the hydatid cyst in radiography, CT scan, and ultrasonography. Serological confirmation through immunoassay can also be done.
Treatment is by the surgical removal of the cysts followed by a course of albendazole. Infection can be prevented by good hygiene and by drinking treated water.
Hence, the term Echinococcus granulosus matches with (E) hydatid cyst.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 2MC
The only ciliate to cause disease in humans is Balantidium. This is a parasite of ciliate protozoa. This parasite is surrounded by cilia. The trophozoites use cilia for locomotion. It causes Balantidiasis in humans. Its normal host is pig.
The parasite is asymptomatic in pig. It infects the humans through feco-oral route. The cysts are ingested through water and food contamination. In healthy individuals it does not cause serious problems of gastrointestinal tract. In people with malnutrition infection occurs due to low acidity in the stomach. In acute cases, diarrhea may be very severe. Perforation of colon also occurs in acute infections. Hence, the correct option is (b) Balantidium.
Naegleria is not a ciliate. It is classified as amoeba. They are protozoa that have no defined shape and move with the help of pseudopodia. Naegleria may assume flagellated form also. Naegleria infection causes amebic meningoencephalitis. Hence, the option (a) is not correct.
Fasciola comes under genus trematodes. It is a helminthic parasite of humans. They belong to liver flukes. It is not a protozoan ciliate. Fasciola hepatica and Fasciola gigantica are two species of Fasciola. Acute infection occurs when the parasite moves from the intestine to the liver. Chronic infection starts when fluke migrates into bile ducts. Hence, the option (c) is not correct.
Trypanosomes are flagellate protozoa. It is not a ciliate. They cause various diseases including sleeping sickness by Trypanosoma brucei and Chagas disease by Trypanosoma cruci. Hence the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 2MTF
The statement “examination of stools samples can reveal the presence of Naegleria parasites” is false.
Naegleria is a protozoan parasite. It affects the brain and causes severe damage. Naegleria fowleri affects humans. These amoebae are seen in ponds, lakes, swimming pools and dialysis units. So, people who swim in the pools, lakes, rivers and in swimming pools with inadequate chlorination can inhale this parasite through their nose.
People who use contact lens get this infection by washing and storing their lens in unsterile tap water. This becomes a focal point for this infection.
When this amoeba enters the brain, it causes amoebic meningoencephalitis. This causes severe headache, fever, destruction of neurological tissues that leads to hemorrhage and coma. This results in death within a week. This parasite assumes flagellated form along with its amoeboid and cyst stages.
Hence, the correct statement is “examination of corneal scrapings, cerebrospinal fluid and also by taking material for biopsy can reveal the presence of Naegleria parasites.”

Microbiology with Diseases by Taxonomy Chapter 23 Answers 2SA
The transmission of amoeba Entamoeba is by ingestion of cysts. These cysts are ingested through contaminated water and food. When the human excreta are used to manure the crops and where the sanitation is not proper, the carriers of the parasite increase. There are no animal reservoirs for this parasite. But, human carriers continuously transmit this parasite. Fecal contamination of hands and oral-anal intercourse are also causes of the transmission. As the cysts are hard, normal water treatment will not eliminate the cysts.
The transmission of Acanthamoeba is through direct contact. Through the cuts or scratches on the skin, through the abrasions caused by the contact lens in the conjunctiva or any injury, the trophozoites can enter the humans. The parasite may enter the host while swimming, if the water is contaminated with the parasite.
In the case Naegleria, the mode of transmission is through inhalation. When the swimmers swim in the water contaminated with trophozoites of this parasite, the trophozoites enter the nasal mucosa and multiply. The trophozoites enter the brain and cause amebic meningoencephalitis.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 3CT
The intestinal microbes affecting the patients with HIV (Human Immune Virus) increase the disease progression. In these patients, the gut immunity fails and the pathogens cross the intestinal mucosal barrier and enter the circulation, causing great loss of gut residing CD4+ T-cells.
Cryptosporidium causes diarrhea, which is self-limiting in people with normal immune system. In AIDS (acquired immunodeficiency syndrome) patients, the symptoms are severe and fatal often. In AIDS patients, this parasite resolves very slowly or does not resolve. It causes watery diarrhea with greatly reduced ability to absorb important nutrients through the intestine.
Visceral leishmaniasis in AIDS patients is a problematic condition. Toxoplasmosis is severe in AIDS patients. The immune system fails, as the pseudocysts reactivate. Patients with AIDS will have severe episodes of malaria, as they have poor immune system.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 3FB
African sleeping sickness is caused by Trypanosoma brucei, but not by Trypanosoma cruzi.
African sleeping sickness is a caused by parasite protozoan Trypanosoma brucei by the insect vector tsetse fly. This parasite has two variants namely Trypanosoma brucei gambeinse, which occurs in western Africa and Trypanosoma brucei rhodesiense, which occurs in eastern and southern Africa.
This sickness is also called African lethargy. This disease is seen mostly in equatorial and subequatorial savanna and is endemic in sub-Saharan Africa. One third of the populations of Africa are at risk of getting this disease.
The epimastigote stage of this parasite changes into infective trypomastigote in the salivary gland of male or female tsetse fly. These infective forms are injected into the humans or animals during blood meal. These parasites move throughout circulatory and lymphatic system and reproduce by binary fission. In this stage, the patient experience lymph node swellings. This may lead to anemia, cardiac problems, and kidney problems.
Some of the trypomastigotes enter the central nervous system. At this stage, there will be disruption in the sleep cycle. Hence, this disease got this name. Along with this, there will be muscle weakness, tremor, confusion, and hemiparesis.
In the absence of treatment, there will be mental deterioration, and organ failure, which will lead to death. Therefore, the correct answers are brucei and cruzi.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 3M
The term Fasciola spp matches with (A) Miracidia.
Fasciola is a trematode. The eggs of this trematode hatches in the fresh water and miracidia forms. It seeks the intermediate host that is snails. The miracidia then undergoes two or three cycles of asexual reproduction inside the snail. Then cercariae larvae are produced.
Miracidia is a free moving form and is covered with cilia. It develops into sporocyst inside the snail.
There are two species of Fasciola. One is Fasciola hepatica and the other is Fasciola gigantica. They cause infection in cattle and sheep. When the humans ingest the metacercariae from aquatic plants like water cress, they get infected. The encysted larvae migrate from the large intestine to the liver and then to the bile duct to reside and mature there.
Heavy infections with this parasite can cause liver failure. Hence, the term Fasciola matches with (A) Miracidia.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 3MC

  • The regular sexually transmitted diseases are caused by an organism, known as trichomonas. It causes trichomoniasis. This infection is caused in urogenital tract. The common site of this trichomoniasis is urethra and vagina in women. In men, this protozoan parasite lives in urethra and prostrate. The only reservoir of Trichomonas vaginalis is the genital tract of humans. Hence, the correct option is (a) Trichomonas.
  • Entamoeba is a protozoan parasite under the classification Ameoeba. It causes amoebiasis. The active stage of this parasite is trophozoite stage. This stage exists only in the host organism and in loose feces freshly passed. Infection occurs by drinking contaminated water with cysts. These cysts can be ingested due to fecal contamination in food and also due to oral-anal intercourse. Entamoeba is not an organism that causes regularly sexually transmitted organism. So, the option (b) is incorrect.
  • Trypanosoma is not a regularly sexually transmitted organism. It is a protozoan flagellate parasite. They are mainly transmitted by a vector. Trypanosoma cruzi is transmitted by kissing bug and Trypanosoma brucei is transmitted by tsetse fly and causes Chagas disease and sleeping sickness respectively. Hence the option (c) is incorrect.
  • Enterobius is not a regularly sexually transmitted organism. This is commonly called pinworm. It is a nematode. It is a parasite which lives in the human intestine. It causes enterobiasis. This parasite is transmitted by ingestion through human to human. The eggs of the worms are deposited around the anus and are transmitted by contamination of food, water, bathroom taps, bed linen, clothes and so on. The eggs can be airborne and can be dispersed and can enter mouth or nose through inhalation. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 3MTF
The given statement is true.
Trypanosoma brucei is a flagellated protozoan parasite. It causes trichomoniasis. This parasite is transmitted by sexual contact only. It lives in the vulva and vaginas of women and in men, in urethra and prostate gland. They cannot live outside the host for a long time.
In the life cycle of trichomonas there is no cystic stage. So, trophozoites are transmitted directly. Trichomoniasis mostly occurs in patients who are already having sexually transmitted diseases.
Women with vaginosis due to this infection will have foul smelling purulent vaginal discharge, abdominal pain, dysuria, and painful coitus. Because of this infection, the vaginal endometrium is damaged. This increases the susceptibility of women to HIV (Human immuno deficiency virus) infection. Men having this trichomanal infection are usually asymptomatic.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 4CT
Sickle cell trait is advantageous to people living in malaria endemic areas. The people having this trait have hemoglobin S. It is an abnormal type of hemoglobin. The normal hemoglobin is A.
This hemoglobin S makes the erythrocytes to become sickle shaped and resist the penetration of the malarial parasite into the erythrocytes. Hence, people with this trait will have survival advantage and there will be less mortality due to malaria when Plamodium falciparum is the causative parasite.
The sickle cell trait may cause renal medullary carcinoma, hematuria, urinary infection, and sudden death during exertion. Hence, this trait is not advantageous in malaria free areas.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 4FB
The parasitic amoeba Entamoeba can be acquired by ingestion.
Entamoeba causes amoebic dysentery. Entamoeba histolytica lives in the digestive tracts of human. In less developed countries, due to the usage of human excreta as a fertilizer for crops, this parasite is predominant. There are numerous human carriers of this disease in industrialized populations also. So, there is continuous transmission of this parasite.
Infection occurs through ingestion of cysts. Food and drinking water gets contaminated with feces containing the cysts of this parasite. Also during oral-anal intercourse the cysts are ingested. The parasite can be ingested due to the contamination of hands with fecal matter.
There are three types of amebiasis. One is luminal amebiasis, in which the trophozoites remain asymptomatic and it happens with rather healthy individuals. The second one is invasive amebic dysentery, in which diarrhea, colitis, with amebic dysentery. The third one is invasive extraintestinal amebiasis. This can be fatal if not treated. Therefore, the correct answer is Entamoeba.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 4M
The term Leishmania spp matches with (H) Amastigotes.
In Leishmaniasis amastigote stage occurs in vertebrate host.
Leishamania is a protozoan parasite and causes Leishmaniasis. It is transmitted by the sand fly. The promastigotes are infective stage of this parasite. This stage of the parasite is injected into the humans by the sand flies during the blood meal.
These promastigotes are phagocytized by macrophages and are changed into amastigotes. They increase and multiply inside the macrophages by binary fission. Then the macrophages rupture releasing the amastigotes, which in turn affect the other macrophages.
During the initial stages of infection, the macrophages responds, but it is not sufficient to destroy the intercellular amastigotes. Inflammatory responses are continuous due to infection of new macrophages. As the number of macrophages decreases, the immune response also declines.
In visceral leishmaniasis, the macrophages spread the amastigotes to liver, spleen, lymph nodes, and so on. If untreated, this disease can be fatal.
The amastigotes are identified microscopically in skin lesions, spleen, and bone marrow samples. This is a diagnostic feature of leishmaniasis. Hence, the term Leishmania matches with (H) Amastigotes.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 4MC
Leishmania species are transmitted by sand flies. Leishmaniasis is caused by this protozoan parasite. It is zoonosis, that is, it is a animal disease transmitted to humans. Female sandflies inject the promastigotes, the infective stage of this parasite into humans. These promastigotes are phagocytized by macrophages and are changed into amastigotes. They affect the cells and tissues depending on the species of Leishmania and the clinical manifestations also differ according to that. Sand flies ingest the macrophages when they bite an infected person. In the sand fly’s midgut the parasite undergo changes and become promastigotes and then into metacyclic promastigotes. In this stage, the parasite migrates to the proboscis of the sandfly.
Hence, the correct option is (a) sand flies.
Leishmania species are not transmitted by tsetse flies. These flies are vectors of trypanosome brucei which cause human sleeping sickness. They suck the infected blood from the vertebrate host and inject the parasite into uninfected animals. Hence, the option (b) is not correct.
Kissing bugs do not transmit Leishmania species. These bugs feed the blood of vertebrates and are vectors of Trypanosoma cruzi, which cause Chagas disease. These bugs feed from the blood vessels of lips, hence got this name. Inside the hindgut of the bug, epimastigotes develop into trypomastigotes which are infective stage of the parasite. Hence, the option (c) is incorrect.
Mosquitoes do not transmit Leishmania species. Mosquitoes are vectors for the transmission of many parasitic and viral infections. Anopheles mosquito is the vector for plasmodium which causes malaria. Female mosquitoes of Culex, Aedes and Anopheles are vectors of microfilaria larvae. Hence, mosquitoes do not transmit Leishmania species.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 4MTF
The given statement is true.
Trypanosoma brucei is transmitted by an insect vector called tsetse fly. They cause the disease African sleeping sickness. This is seen commonly in equatorial and sub equatorial areas of Africa. If not treated early, this is 100% fatal.
In the male and female tsetse flies, the epimastigote stage of this parasite changes into trypomastigotes. When the mosquito bites the human, the trypomastigotes enter the blood circulation. Some of them enter the central nervous system and cause meningoencephalitis. This cause abnormal neurological functions, and coma and leads to death in six months time of onset of symptoms.
The parasites in the blood circulation causes a condition by changing its surface glycoproteins so that the patient is incapable of being freed from the infection and never can become immune to that infection.
Trypanosoma cruzi is transmitted by kissing bugs scientifically named triatomine bug. This bug deposits its feces with the trypomastigotes in the skin. Scratching this area by the host helps the trypomastigotes to penetrate the skin.
This parasite causes Chagas disease. In its acute stage, amastgotes are seen in the swelling at the site of bite. The other stage is that this parasite affects the internal organs such as heart, colon, and esophagus and so on. This parasite induces heart disease and can cause death.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 5CT
Trypanosoma cruzi causes Chagas’ disease. The clinical manifestations of this disease are chagomas, which are swellings at the sites of bite by the kissing bug. It is an acute stage.
The trypomastigotes enter the blood stream and penetrate heart muscles, macrophages, and get changed into amastigotes. This is a generalized stage. Fever, lymph nodes enlargement, inflammation of heart muscles (myocarditis), spleenomegaly, inflammation of esophagus and colon are notable symptoms of this stage.
The amastigotes undergo binary fission and multiply. Some of them infect other cells and some of the amastigotes change into trypomastigotes and circulate in the blood. They are ingested by the kissing bug during the blood meal. A chronic stage comes after this and it is for years.
Amastigotes form pseudocysts in the heart muscles causing congestive cardiac failure. This is called asymptomatic stage. The leading cause of death due to this parasite in Latin America is parasite induced heart disease.
Trypanosoma brucei causes African sleeping sickness. This disease if untreated can go through three stages of clinical manifestations.
Number one is wound formed at the site of the bite by tsetse fly. The fly injects trypomastigotes into the wounds. This lesion has rapidly dividing parasites and dead tissue.
Second stage is trypomastigotes, they enter the lymphatic and blood circulation and undergo binary fission and multiply. The parasite in the blood circulation cause fever, head ache, and swelling of lymph nodes.
The third stage is some trypomastigotes. They enter central nervous system (CNS). The manifestations of this stage are meningoencephalitis. The patient experiences headache, abnormal neurological functions, and coma. The patient may die within three to six months from the time of onset of symptoms.
The differences in the clinical manifestations are as follows:

  1. In Trypanosoma cruzi, the trypomastigotes enter heart muscles, spleen from the blood circulation, but in Trypanosoma brucei, the trypomastigotes enter the central nervous system.
  2. The cause of death is due to parasite induced heart disease in the case of Trypanosoma cruzi, while the cause of death is due to meningoencephlitis in the case of Trypanosoma brucei.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 5FB
Plasmodium vivax and Plasmodium ovale both can form dormant hypnozoites.
Other plasmodium species do not have hypnozoites.
Latent hepatic stage of these parasites is called hypnozoites. These hypnozoites cause malaria even long time after the mosquito bite.
The sporozoites are injected into the human by the bite of female anopheles mosquito. They enter the blood stream and enter the liver and undergo schizogony. Merozoites are produced, which rupture the liver cells and enter into blood circulation.
In the case of Plasmodium vivax and Plasmodium ovale, a resting stage of the parasite is formed. This is called hypnozoites. Hypnozoites remains dormant in the liver cells for years. It is reactivated at any time causing relapses of malaria. Therefore, the correct answer is hypnozoites.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 5M
Plasmodium falciparum matches with (C) Schizogony and (G) trophozoites.
This parasite has three stages. In the first stage, the erythrocytic phase, the sporozoites of this parasite are injected into humans by female anopheles mosquito. These sporozoites enter the liver tissue and undergo schizogony in the liver cells. As a result of schizogony, merozoites are produced. They rupture the liver cells and enter the blood circulation.
These circulating merozoites enter the erythrocytes. This is erythrocytic cycle. The merozoites change into trophozoites. They can endocytize the hemoglobin of erythrocytes. Trophozoites undergo schizogony and more merozoites are produced. These cause the lysis of erythrocytes. Erythrocytes are destroyed continuously and cyclically.
Plasmodium falciparum causes blackwater fever. In this disease, large amount of erythrocytes are destroyed and results in renal failure. Dark colored urine is produced due to excretion of hemoglobin.
Erythrocytes become rigid and lose its elasticity due to the parasite protein being inserted on the surfaces of infected erythrocytes. This causes blockage in the flow of blood and tissue hemorrhages. This leads to tissue death. Cerebral malaria results if the tissue death happens in the brain. Within 24 hours of the onset of symptoms, Plasmodium falciparum can be fatal.
Hence, the term Plasmodium falciparum matches with the options (C) schizogony and (G) trophozoites.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 5MC
The intracellular infection stage of leishmaniasis is amastigote. Leishmaniasis is transmitted by female sandflies. These sandflies inject metacyclic promastigotes as it bites the host. The macrophages phagocytize the promastigotes and amastogotes are formed. These amastigotes multiply in number in the infected cells. As the macrophages rupture, the amastigotes are released. They infect other macrophages and also circulate in the blood stream. At this stage it is ingested by other sand fly.
Hence, the correct option is (d) amastigote.
Miracidia are free swimming larvae of trematodes called flukes. These miracidia are within 24 hours of hatching, enter into a mollusc host. After two or three cycles of asexual reproduction, they become cercaria larva. The cercariae leave the snail host and enter the next host depending on the type of parasite whether it is blood fluke, liver fluke and so on. Hence, the option (a) is incorrect.
Metacercaria is cercariae, the larvae of fluke, encysted and in resting stage. The cercariae, larval stage of intestinal and liver fluke, encyst on vegetation. In lung flukes and some of the liver and intestinal flukes, the cercariae encyst and metacercariae is formed inside a second intermediate host. Hence, the option (b) is incorrect.
Bradyzoite is one of the stages of zoonotic organisms like Toxoplasma gonadi. It is slow growing form and hence got this name bradyzoite. The sporozoites reproduce asexually and produce bradyzoites. Around the masses of cells with bradyzoites thick walls are formed. These form pseudocysts. These pseudocysts enter the cat’s intestine and these parasites become gametes. Hence the option (c) is not correct.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 5MTF
The given statement is true.
This parasite is a protozoan parasite and belongs to the genus Plasmodium. It is a more virulent species. Its insect vector is female anopheles mosquito. Malaria caused by this parasite is the most serious form of malaria and it is also called malignant malaria. This falciparum malaria has many complications and its mortality rate is high. In Africa most of the cases of malaria is falciparum malaria.
As soon as humans are bitten by the infected mosquito, sporozoites are injected and enter the blood stream. Within 30 minutes sporozoites all invade the liver cells. In the liver merozoites are produced. They are released from the liver cells by bursting them and enter the red blood cells. Schizonts are produced. Each schizont has 12-16 merozoites. When the red blood cells get ruptured and the merozoites are released, the patient experiences fever with rigor.
The sequestration is the distinctive property of Plasmodium falciparum. They change the surface properties of infected erythrocytes and make them to adhere to the blood vessels. So, there is obstruction of blood circulation in the capillaries, which leads to multi organ failure. Mainly it is brain and it is called cerebral malaria.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 6CT
In the case of Trypanosoma brucei, the infections are characterized by cyclical waves of parasitemia. That is, presence of the parasite in the blood circulation. It occurs every 7-10 days.
For every cycle, the parasite changes its surface glycoproteins and thereby surface antigen. By the time the host produces the antibodies for the glycoprotein, the parasite already produces new set of glycoproteins.
This makes the host always one step behind the parasite. So once infected with this parasite, the host is not able to clear the infection and never can become immune to this disease.
Hence, it is difficult to create a successful vaccine for Trypanosoma brucei.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 6FB
Of the parasitic helminthes discussed in this chapter, the only one transmitted by mosquitoes is Wuchereria.
Wuchereria is a parasite, which causes filariasis. It affects the lymphatic system of the humans.
Humans are definitive hosts and mosquitoes are intermediate hosts. Culex, Anopheles, and Aedes mosquitoes are common mosquito vectors. These mosquitoes have preference for human blood.
Inside the mosquito, the microfilaria changes into moving larvae, which are injected into humans during blood meal. These larvae enter into the blood circulation and enter the lymphatic system. Mainly they affect lower extremities and genital organs.
In endemic areas, the prevention is taken, which focuses against the mosquito bites. Mosquito repellents and using mosquito net during sleep are effective means of protecting from mosquito bites. Hence, the correct answer is Wuchereria.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 6M
Plasmodium vivax matches with (c) schizogony, (G) trophozoites, and (I) hypnozites.
Plasmodium vivax infection occurs in humans when a female anopheles mosquite infected with this parasite bites humans. The sporozoites are injected into the blood circulation during the blood meal and reach liver and undergo schizogony. This stage is called erythrocytic phase, which is outside the erythrocytes.
The merozoites are formed after number of binary fissions. The liver cell ruptures and the merozoites are released into the blood stream.
In some occasions, the sporozoites remain dormant for few weeks or even months. They do not immediately start dividing after entering the liver cell. These are called hypnozoites. The period of dormancy varies for each hypnozoite. The factors which are responsible for sudden triggering of the growth of hypnozoites are not yet known.
When merozoites enter red blood cells, another stage of the parasite is developed called trophozoites. These trophozoites undergo schizogony and produce more merozoites. These merozoites in turn lyse the red blood cells. The red blood cells with this parasite are twice as big as the normal cell. The red blood cells with trophozoites inside are the diagnostic feature of malaria.
Hence, the term Plasmodium vivax matches with (C) schizogony, (G) trophozoites, and (I) hypnozoites.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 6MC
In malaria, the erythrocytic cycle occurs in the red blood cells. The merozoites of the parasite Plasmodium enter the red blood cells, which are called trophozoites. The diagnostic finding of malaria is trophozoites, inside the red blood cells. Trophozoites endocytize hemoglobin of the Red blood corpuscles. Through schizogony, more merozoites are produced and lyse more red blood cells. The erythrocytic lysis takes place cyclically depending on the species of involved plasmodium. Some merozoites develop into gametocytes within the red blood cells whereas most of the merozoites go on in the lysis of new erythrocytes.
Hence, the correct option is (b) Erythrocytic cycle.
The exoerythrocytic phase takes place outside the erythrocytes. During the mosquito bite, the sporozoite stage of the parasite Plasmodium is injected into the body. These sporozoites along with blood stream reach the liver and undergo schizogony over the period of one or two weeks. Due to this, merozoites are formed, which rupture the liver cells and enter the blood stream. The free merozoites penetrate the erythrocyte and then the erythrocytic cycle starts. Hence, the option (a) is incorrect.
The sporogonic phase does not occur in the red blood cells. When the mosquito bites the infected person, the gametocytes present within the red blood cells are ingested by the mosquito. The erythrocytes are digested inside the digestive tract of the mosquito, and the gametocytes are freed. The male gametocytes fertilize the female gametocytes and form zygotes. Then ookinete is formed, which becomes oocyst. This oocyst undergoes meiosis. After a period of ten to twenty days, due to rupture of oocytes, thousands of sporozoites are released. They migrate to the salivary glands of the mosquitoes. Hence, the option (c) is incorrect.
Amastigote phase does not occur inside the erythrocytes in malaria. Leishmania has two stages. One is amastigote, which lack flagella. They multiply inside the macrophages and monocytes of the mammalian host. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 6MTF
The given statement is true.
Toxoplasmosis is caused by protozoan parasite Toxoplasma gondii. The primary host is felid. This parasite infects humans and most warm-blooded animals. Transmission of the parasite is through ingestion of feces of infected cat. Cat is the main source of infection for humans, and eating raw pork also contributes to the infection.
Routine investigation for toxoplasma is done for pregnant women. Transplacental transmission of this parasite is very dangerous to the fetus in the first three months of pregnancy.
Some of the effects of toxoplasmosis during pregnancy by the transplacental transmission of the parasite are:

  1. Spontaneous abortion
  2. Intra uterine death and still birth
  3. Congenital anomalies of the fetus including microcephaly
  4. Inflammation of the retina of the fetus, blindness and anemia.
  5. Ocular infections can be persistent for many years.

 

Microbiology with Diseases by Taxonomy Chapter 23 Answers 7CT
Plasmodium causes these signs and symptoms. The symptoms of malaria are fever, chills headache, and vomiting.
Two weeks after the erythrocytic cycle starts, there are enough number of parasites in the blood to cause these symptoms. Hence, the patient had one month history of these symptoms.
Diagnostic sign of malaria is to take the blood smear and it shows the trophozoites inside the erythrocytes.
Treatment depends on the species of the parasite and severity of the disease. The anti- malarial drugs are mefloquine, chloroquine, atovaquone in combination with proguaril.
The WHO (world health organization) prescribes the drug called artemisinin, which is taken from a shrub. This shrub is used in Chinese traditional medicine for malaria. The medication for fever can be given and also blood transfusion can be given if required.
This is not a rare disease in Florida, because the mosquito vectors breed in wet lands.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 7FB
The helminthes, which can directly penetrate the skin of humans to establish infection, are Ancylostoma, Necator and Schistosoma.
Ancylostoma is some species of hookworm. Usually humans are infected by this hookworm by walking with bare foot over contaminated ground. The larvae penetrate the skin and enter the blood stream. Then they enter the lungs and pierce the alveoli and enter the trachea, from where it is swallowed up and carried to the intestine. The point of entry may get an itching patch, which is called ground itch.
Necator is a genus of nematodes. Eggs of these worms are passed along with the stools from the infected human. These eggs hatch up in few days as infective larvae come up. This can live upto five weeks in the soil. These larvae penetrate the human skin and enter the circulatory system.
Schistosoma is trematode called blood fluke. Eggs are passed outside to the environment along with urine or stools. There they enter the intermediate host, snail. The other larval stage of this parasite enters the human host by penetrating the skin.
Hence, the correct answers are Ancylostoma, Necator, and Schistosoma.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 7M
Taenia spp matches with (F) cysticerci.
Taenia saginata is the beef tapeworm and Taenia solium is pork tapeworm. Cattle are the intermediate host of Taenia saginata and pig is the intermediate host of Taenia solium.
Taenia saginata has human as their definitive host. The eggs voided by infected humans along with feces are ingested by cattle and onchospheres are formed in the intestine. This onchospheres enter the circulation of the host, penetrating the intestine and cysticercus bovis is formed in the muscle fibers and in liver or lungs. Humans get infected by ingestion of this cysticercus.
In Taenia solium, in which the humans are definitive hosts, the infection is caused by ingestion of eggs by contaminated water or food. Oncosphers hatch in the intestine of humans and migrates into muscles, brain, or other tissues. Here, they are formed into cysticerci.
If the cysticerci form in the brain tissue, it results in neurocysticercosis. Eggs are ingested by pigs via contaminated food or water. The eggs develop into cysticerci in pig muscles. Humans get infected when they eat undercooked pork with cysticerci. Hence, the term Taenia spp matches with (F) cysticerci.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 7MC
The definitive host for Toxoplasma gonadii is cats. This parasite can reproduce sexually only in cat’s intestine. This protozoan parasite causes toxoplasmosis. The infection with this parasite does not produce any symptoms in healthy individuals. This parasite is transmitted by ingestion of cysts. It is also transmitted from the mother to fetus. In humans it reproduces asexually. All the warm-blooded animals including humans are intermediate hosts.
Hence, the correct option is (b) mosquitoes.
The definitive host of Toxoplasma gonadii is not humans. Humans and other warm-blooded animals are infected by this parasite by ingestion of cysts. By consuming uncooked meat, containing the cysts of parasite or by water and vegetable contamination the humans are infected. The parasite reproduces asexually in human beings. So, humans are intermediate hosts of this parasite. Hence the option (a) is not correct.
The birds are not definitive hosts of Toxoplasma gonadii. Almost all the warm-blooded animals can be infected by this parasite. So, birds can be intermediate hosts of this parasite. Hence, the option (c) is not correct.
Mosquitoes are not definitive hosts of Toxoplasma gonadii. The mosquitoes do not play any part in the life cycle of this parasite. The sexual reproduction of this parasite occurs only in cats and the asexual reproduction occurs in any warm blooded animals like humans, cats, and birds. Hence, the option (d) is not correct.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 7MTF
The given statement is true.
Taenia solium is also called pork tapeworm. Human is the definitive host and pig is the intermediate host. As the infected human passes the eggs in the feces, these eggs are ingested by pigs. These onchospheres hatch and circulate in the musculature of the pigs and humans. Cysticercus develops in the muscles of pigs and humans. By ingesting the infected pork, humans get the infection.
Man becomes the intermediate host of Taenia solium rarely by ingesting the eggs or proglottids. Larvae released from these eggs change into cysticerci in human. That is the dead end of the parasite. This happens accidentally.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 8CT
The diagnosis is Schistosomiasis. This is caused by blood flukes. The name of the species is Schistosoma haematobium.
In this infection, the eggs of the parasite moves into the bladder and ureters, causing hematuria and blockage due to fibrosis and calcification. This may cause bladder cancer in some geographical areas.
Diagnosis is done by the presence of eggs with spines in urine samples. The treatment for blood fluke infection is done by praziquantel. Improved sanitation and avoiding direct contact with the contaminated water can prevent infection.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 8FB
A trematode that can be acquired by eating raw or undercooked food vegetable is Fasciola.
Fluke eggs are passed along with feces or urine from infected people, when those eggs are voided in the fresh water. When this eggs hatch, the larvae called miracidia are released in the water. These larvae enters the snail of a respective species. Cercariae larvae are produced in the snail, as it is intermediate host of the fluke. These cercariae come in contact with humans and penetrate the skin of the host.
In the case of liver and intestinal fluke, cercariae get settled on plants and become encysted metacercariae.
In the case of lung fluke and some of liver and intestinal flukes, the encysted metacercariae are formed inside a second intermediate host.
People get infection by ingestion of metacercariae by eating contaminated raw watercress or other water plants.
Human is the definitive host. After interning the definitive host, the parasite migrates to their respective site in the human body. Hence, the correct answer is Fasciola.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 8M
The term Toxoplasma gondii matches with (B) bradyzoites.
Toxoplasma is a protozoan parasite. This parasite causes toxoplasmosis. In healthy persons, this infection is asymptomatic. In people with weakened immunity, this causes serious illness.
The definitive hosts are cats and the intermediate hosts can be humans or birds or cats.
This parasite has different cellular stages. They are as follows:

  • Tachyzoites – quick in multiplying
  • Merozoites – divides quickly and multiply the number of parasites inside the definitive host before sexual reproduction.
  • Bradyzoites – slow in dividing and forming cysts.
  • Sporozoites – multiply asexually to form bradyzoites.

The cat passes out oocysts along with feces. These oocysts survive in the moist soil and gets matured producing sporozoites inside. As the rodents ingest the oocysts, sporozoites are released and enter the rodent’s muscles, digestive organs, brain, and also lymph nodes. Asexual reproduction takes place and sporozoites multiply and bradyzoites are produced. Thick walls are formed around the bradyzoites and form pseudocysts.
For sexual reproduction, the parasite returns to the cat. This is made possible by inhibiting the part of the brain of the rodent that processes the odor and induces fear of the cat. So, the infected rodent is eaten easily by the cat. So, the bradyzoites are released inside the cat’s intestine and complete its sexual reproductive cycle. Hence, the term Toxoplasma gonadii matches with (B) bradyzoites.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 8MC
Tapeworms are transmitted via consumption of an intermediate host. This parasite has mammals as their definitive and intermediate hosts. The definitive host gets this infection by eating and intermediate host as its prey. The eggs of this parasite are ingested through contaminated food and water by the intermediate host. By eating undercooked meat of this intermediate hosts, the cysticercus of this parasite enter the humans, which are definitive hosts. Hence, the correct option is (a) consumption of an intermediate host.
The tapeworms are not transmitted via consumption of the definitive host. The definitive host is human. The infected human passes eggs of this parasite with the feces. The foods contaminated with these eggs are consumed by the intermediate host like pigs. The ingested eggs hatch larvae migrate to the tissue penetrating the wall of the intestine. They develop into cysticercus in muscle. Hence, the option (b) is incorrect.
Tapeworms are not transmitted via vectors such as mosquitoes. Mosquitoes do not have any role in the life cycle of tapeworm. Tapeworm transmitted to the humans via consumption of and intermediate host. Hence, the option (c) is not correct.
Tapeworms are not transmitted via consumption of adult tapeworms. The intermediate hosts like pigs get infected by consuming the contaminated food, which has eggs of the tapeworm. Hence, the option (d) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 8MTF
The given statement is false.
Fasciola hepatica can be acquired by eating infected water plants. This parasite is called liver fluke and it infects humans and many mammals. Its distribution is worldwide. Sheep and cattle are killed due to this infection and create big economic loss.
The intermediate host for this parasite is fresh water snail in which the asexual reproduction takes place. The eggs are passed along the feces of infected mammals and humans. These eggs hatch into miracidia in warm conditions. The miracidia find snail host. Small cercariae come out of snail host and encyst as metacercariae on the water plants. Sometimes humans eat uncooked water cress. Thus, the parasite gets ingested by humans sometimes.
Hence, the correct statement is “Fasciola hepatica can be acquired by eating infected water plants.”

Microbiology with Diseases by Taxonomy Chapter 23 Answers 9CT
In rare occasions, humans become intermediate hosts of Taenia solium if the eggs or gravid proglottids are ingested by humans rather than cysticerci.
The larvae from the eggs are changed into cysticerci in the muscle of the humans. This happens when the humans become intermediate host accidentally.
This is the dead end of the parasite, because no host will eat human flesh. So, humans with cysticerci are the dead end of that parasite.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 9FB
Hookworm disease is caused by Ancylostoma in the Middle East.
This disease is called anchylostomiasis. This sucks blood from the humans from the walls of the intestine. If the hook worm is present in huge numbers, it will cause iron deficiency anemia.
Ancylostoma duodenale is one of the hookworms, which infect the humans. They are distributed throughout the Americas, Africa, the Middle East, North Africa, and southern Europe.
The other hookworm is Nacator Americans. It is mostly seen in the Americas and Australia.
The eggs of both of these worms are not distinguished. The eggs are deposited in the soil and hatch into larvae, which in turn change into an infective larvae. This larva penetrates the human skin and enters the humans.
By improved sanitation and education and using footwear can reduce the risk of infection. Therefore, the correct answer is Ancylostoma.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 9M
Trypanosoma matches with (J) Trypomastigotes.
Trypanosoma is a flagellate protozoan.
In the case of Trypanosoma cruzi, Chagas’ disease is caused. Transmission of the parasite is through the kissing bug. Inside the hind gut of the bug, the epimastigote of the parasite is changed to trypomastigotes. These trypomastigotes are voided along with the feces of the bug in the site of the bite. When the host scratches the itchy wound made by the bug, the trypomastigotes enter the body through the wound and enter the blood circulation. Then they enter the heart muscle cells or macrophages.
In the case of Trypanosoma brucei, African sleeping sickness is produced. Transmission of this parasite is through tsetse fly. Inside the salivary gland of the tsetse fly, the epimastigote of the parasite matures into trypomastigotes, which are infective. During the blood meal, trypomastigotes are injected into the blood circulation and lymphatic circulation. Some enter the central nervous system (CNS).
Hence, the term Trypanosoma matches with (J) trypomastigotes.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 9MC
The parasite that cannot be killed by routine boiling or other than cryptosporidium is Giardia. Giardiasis is a waterborne gastrointestinal disease. It has very hard protective cover and can survive in the environment for months. As it cannot be killed by routine boiling, filtering water is necessary to remove this parasite from the drinking water. Hence, the correct option is (a) Giardia.
Trypanosoma brucei cause African sleeping sickness and Trypanosoma cruzi causes Chagas disease. Transmission occurs through tsetse fly and kissing bugs. This parasite is transmitted via vectors. So, the option (b) is incorrect.
Toxoplasma is a protozoan parasite. This parasite is transmitted by consuming raw or undercooked food contaminated with cysts of this parasite. Water and vegetables contaminated with oocysts cause infection. Prevention is to cook the meat thoroughly or deep-freeze meats. Hence, the option (c) is incorrect.
Plasmodium belongs to Apicomplexan parasites. This parasite causes malaria. This disease is transmitted by mosquito bites. There are two hosts for this parasite. It is a vector- mosquito and a vertebrate host. Hence, the option (d) is not correct.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 9MTF
The given statement is true.
Snails are intermediate hosts of schistosomiosis parasite and humans are definitive hosts. In developing countries people use water contaminated with snails. Poor sanitation facilities are also a cause of this infection.
In endemic areas, as technology has improved and economy is also stabilized, the incidence of schistosomiosis has also been increased because water reservoirs and improved irrigation system has become a habitat for the snails, which are intermediate hosts of this parasite.
The cercariae escape from the snail into the water. When humans come in contact with the water, it penetrates the skin. The larvae enter into the blood circulation. Here the sexual reproduction takes place. The eggs have distinctive spines. The eggs enter the intestine or urinary bladder and ureters; and are passed outside along with stools or urine.
This parasite produces chronic infection if the eggs lodge in the liver, brain or lungs. Eggs, which are trapped in those tissue die there and cause fatal tissue damage.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 10FB
Enterobius vermicularis and Wuchereria bancrofti are the two parasites demonstrating nocturnal movement, which is important for diagnosis.
Enterobius vermicularis is called pin worm. It’s only host is humans. The mating takes place in the large intestine. The female pinworm comes to the anal area during nights and lays their eggs around the anus. Due to this, scratching is intense around the anal area and bacterial infection may form as secondary infection. So, if the patient complains of intense itching sensation around the anus during nights this is the diagnostic symptom of Enterobius vermicularis.
Wuchereria bancrofti is filarial parasite. It causes filariasis by infection of lymphatic system. Chronic filariasis is called elephantiasis. Humans are definitive hosts and mosquitoes are intermediate hosts. The microfilarial larvae of this parasite live in blood circulation. During day time, it lives in the deep veins and during nights it comes to the peripheral circulation, so that the mosquito vector can be ingested with these larvae during blood meal. This coincidence with the nocturnal feeding habit of the vector is a diagnostic sign of this parasite infestation.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 10M
The term Wuchereria bancrofti matches with (D) microfilaria.
This is a parasitic nematode. This is transmitted by mosquito vectors. This infects the lymphatic system of the vertebrate host and causes filariasis. This can produce chronic disease called elephantiasis.
The first stage larvae are called microfilariae and they move freely in the blood circulation. In the day time, they are in the deep circulation and during the nights they come to peripheral circulation. This nocturnal periodicity coincides with the feeding habit of the vector.
Then it is ingested by the mosquito during the blood meal and matures into juveniles larvae and migrates into the salivary glands of the mosquito. During the next blood meal, it infects the new host. Hence, the term Wuchereria bancrofti matches with (D) microfilaria.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 10MC
The immature fluke stages that infect small intermediate hosts are called miracidia. They are free living larvae. These miracidia hatch within 24 hours and enter the host, snail. They complete two or three asexual reproductive cycles in the intermediate host to become cercaria larva. The cercariae larva leaves the snail host and enters the new host. Hence, the correct option is (d) miracidia.
Metacercariae is encysted cercariae of the fluke. In lung flukes, intestinal and liver flukes, the cercariae encyst within a second intermediate host and become metacercariae. Humans ingest the metacercariae and get infected. Hence, the option (a) is not correct.
Cercariae do not infect small intermediate host. Miracidia infect the small intermediate host. Miracidia after the asexual reproduction become cercariae. These cercariae form a cyst and become metacercariae on vegetation in the case of some intestinal and liver flukes. In some cases of intestinal and liver flukes, metacercariae is formed in second intermediate host. Hence, the option (b) is not correct.
Cysticerci are not the immature fluke stage. It is larval stage of tapeworm. The larvae of Taenia solium causes an infection called cysticercosis. They form cysts in brain and muscles. These cysts are called cysticerci. Hence, the option (c) is incorrect.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 10MTF
The given statement is true.
Wuchereria bancrofti is a parasite, transmitted by mosquitoes and cause lymphatic filariasis. They enter the lymphatic system and the lymph nodes. Adult parasites live in the lymphatic system and reproduce up to seventeen years. During the day time, the larvae stay in the capillaries of the organs and during night time they come to the blood circulation and swim freely. Thereby it coincides with the feeding habit of the mosquito, suitable for transmission.
Damage to the lymphatic system occurs as the disease progress. As the lymphatic vessels are getting blocked there will not be enough drainage of lymph fluid. The areas where the lymph is accumulated, tissues start to enlarge and harden.
Chronic infection causes elephantiasis, in which the parasite lodges inside the lymphatic system. This infection affects mostly lower extremities. It can also affect arm, vulva, breasts, and scrotum.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 11MC
The beef tapeworm is known as Taenia saginata. This parasite lives in both humans and cattle. Humans are definitive host and intermediate host is cattle. The infected humans pass the fertilized eggs along with faeces. These eggs are ingested by cattle and the zygotes are formed as the thick shell of the egg is digested by the digestive enzymes. These zygotes or oncospheres enter the circulation of the cattle. In the circulation, the fluid filled cysts are formed. Cysticercus bovis are the cysts formed in the muscle fibers and also in lungs and liver. By eating undercooked or raw food, humans get this infection. Hence, the option (b) is correct.
Taenia solium is not beef tapeworm. It is pork tapeworm. It has two hosts namely pig and humans. The larvae of this parasite cause cysticercosis in humans. When an infected human passes faeces, the eggs are also shed along. Pigs and other humans get infected by the ingestion of eggs due to contamination. The ingested eggs hatch into oncospheres, which migrate from the intestine and enter the striated muscles, brain, liver, and other tissues also. Here the cysticercae are formed. Hence, the option (a) is incorrect.
Ancylostoma duodenale is not the scientific name of beef tapeworm. It is called hookworm. The hosts of this parasite are humans, cats, and dogs. The filariform larvae penetrate the skin of the host and enter the blood circulation and reach the lungs. It is then coughed up, swallowed, and goes into the digestive tract to the small intestine. Infection with this parasite causes abdominal pain, and loss of appetite. In severe cases, it causes anemia, and protein deficiency. Hence, the option (c) is not correct.
Echinococcus granulosus is not the scientific name of beef tapeworm. It is called hydatid worm. The definitive host is dog. The intermediate hosts are humans and cattle. The infection of the parasite is called hydatid disease. Hence, the option (d) is not correct. Hence, the correct option is (b) Taenia saginata.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 12MC
Enterobius vermicularis is commonly called pinworm. The other name is threadworm. It is a parasite in the small intestine of humans. The infestation of pinworm is called enterobiasis. The mode of transmission is human to human by ingestion of eggs. Dust contaminated with these eggs are airborne and are inhaled and swallowed up. The symptoms due to this infestation are itching around the anal area. Hence, the option (b) is correct.
Hookworm is not the common name of Enterobius vermicularis. It is the term for the Ancylostoma duodenale and Necator americanus. It lives in the small intestines of mammals like human, dog, and cat. Hence, the option (a) is not correct.
Whipworm is not the common term used for Enterobius vermicularis. The roundworm is otherwise called whipworm due to its appearance. It has scientific name Trichuris trichura. Trichuriasis is caused when the parasite infects the large intestine of human beings. Whipworm infestation is common in individuals who are infected with Giardia, Ascaris, and hookworms. Hence the option (c) is incorrect.
Tapeworm is not the common name used for Enterobius vermicularis. The scientific name of tapeworm is Taenia solium. These parasites look like a tape and hence got this name. It has mammals as their definitive host and intermediate hosts. The eggs are ingested by contamination of food and water. Hence, the option (d) is not correct. Hence, the correct option is (b) Enterobius vermicularis.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 13MC
The infective larvae of Necator americanus larvae must pass through human lungs to mature. This parasite lives in the small intestine of hosts. The hosts are humans, cats, and dogs. The unembryonated egg of the parasite becomes embryonated under favorable conditions and hatches. The first stage is called rhabditiform larvae. The second stage molts and third stages larvae are called filariform larvae. This is infective form. This larval from enters the human body by penetrating the skin. It enters the blood circulation and enters the heart and reaches the lungs. Inside the lungs, they enter the alveoli and goes to trachea. From there it gets swallowed up and goes to the small intestine to mature. Hence, the option (c) is correct.
The infective larvae of Necator americanus do not pass through bladder to mature. After penetrating the human skin it enters the circulation and enters the lungs. Then it reaches the digestive tract from the trachea. The larvae attach to the small intestine and mature into adults. Hence, the option (a) is incorrect.
The infective larvae of Necator americanus do not pass through brain to mature. It passes through the lungs to small intestine where they mature. Hence, the option (b) is not correct.
The filariform larvae do not go through the liver. It goes through the lungs and heart along the blood circulation. They burrow through the alveoli and enter the trachea. The larvae mature in the small intestine. Hence the option (d) is incorrect. Therefore, the correct answer is option (c) Necator americanus.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 14MC
Both Plasmodium species and Wuchereria bancrofti are carried by mosquitoes in the genus anopheles. In endemic areas Plasmodium species cause malaria in humans. This Anopheles gambiae mosquitoes are vectors of dangerous malarial parasite called Plasmodium falciparum. Filariasis is caused by Wuchereria bancrofti. Some species of Anopheles mosquitoes are vectors of this parasite and serve as intermediate host of this parasite. Hence, the option (b) is correct.
The Aedes mosquitoes are not the carriers of the Plasmodium species. Aedes mosquitoes are one of the vector species which carries the parasite Wuchereria bancrofti. They have preference for human blood and only humans are infected with this parasite. Aedes mosquitoes are not vectors of Plamodium species. Hence, the option (a) is not correct.
Culex mosquito is not the vector of plasmodium species. But it is carrier of the parasite Wuchereria bancrofti. Female culex mosquitoes ingest the microfilaria during the blood meal. These microfilariae develop inside the mosquito and become larvae. These larvae migrate to the salivary glands and get injected to the next human whom the mosquito bites. Hence, the option (c) is not correct.
Ctenocephalides is not the vector of the plasmodium species and Wuchereria bancrofti. It is a type of flea. There are dog fleas and cat fleas. They breed on dogs and cats. They are blood sucking insects. Hence, the option (d) is not correct. Hence, the correct option is (b) Anopheles.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 15MC
The arthropods responsible for transmitting most of the parasitic diseases are mosquitoes. An arthropod means animal with segmented body, legs with joined segments, with hard external skeleton. The mosquitoes serve as vectors or carriers of many parasites. Some act as hosts of those parasites. They are called biological vectors. These mosquitoes are seen with the host during their blood meal only. The mosquitoes are responsible for spreading malaria and filariasis. Hence, the option (c) is correct.
Fleas are not responsible for transmitting parasitic diseases. They are parasites, which pierce and suck the blood of the host. They are external parasites and also wingless insects. They live on dogs, cats, and human beings. Hence, the option (a) is not correct.
Ticks are responsible for transmitting few parasitic diseases, not most of them. Ticks harbor many diseases causing pathogens difficulty to diagnose. Ticks serve as vector for Babesia microti and causes Babesiosis. This disease is spreading widely as its vector tick has expanded range because of global warming. Hence, the option (b) is not correct.
True bugs are called Hemiptera. They are not responsible for transmitting most of the parasitic diseases. Many species of these bugs are pests of crops. Hence, the option (d) is not correct. Hence, the correct option is (c) mosquitoes.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 16MC
Majority of the cestodes are transmitted via ingestion. Cestodes are also called tapeworms. They live in the digestive tract of vertebrates. Humans are infected by consuming undercooked pork or beef having the cysts of these parasites. The infected human passes eggs along with faeces, which are ingested by grazing animals like cow. These are intermediate hosts and humans are definitive host. Hence, the option (a) is correct.
The majority of the cestodes are not transmitted by vectors. Vectors make a pathway for pathogen to get into the host. This may be done by means of blood sucking. The vectors are not affected by the pathogens, but it transmits the pathogen from one host to other host, thereby successfully transmitting the diseases. In the case of cestodes, the transmission is by the ingestion of eggs or consuming meat having the larvae of the parasite. Hence, the option (b) is wrong.
Most of the cestodes are not transmitted by direct contact, but by ingestion. The cestodes have definitive and intermediate host. Many species of this parasite infect humans after getting consumed by them with undercooked food. Hence, the option (c ) is not correct.
Most of the cestodes do not get transmitted by inhalation. Hence, the option (d) is not correct. Hence, the correct answer is option (a) ingestion.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 17MC
To prevent infection by Giardia, the effective method is to drink only bottled water. Giardiasis is a waterborne gastrointestinal disease, which is commonly seen. Giardia lives in the small intestine of the humans and animals. The mode of transmission is fecal-oral route. It is mainly water contamination with cysts of the parasite. Cysts are hardy. This parasite is found in water, food, and in soil, which are contaminated with feces. Due to the protective outer layer of the shell, this organism can live for months outside the host in the environment. So, water should be sterilized chemically or filtered. Boiling is not sufficient because cysts can survive boiling. So, purified bottled water is an effective way of preventing Giardiasis. Hence, the option (b) is correct.
Sexual abstinence is not the most effective in prevention of Giardiasis. The parasite is transmitted by fecal-oral route. So, one should avoid contact with feces during sexual intercourse to prevent the infection. Hence, the option (a) is not correct.
Use of insect repellent is not the effective prevention of Giardiasis. There is no chemoprophylaxis. The transmission route is fecal-oral. So, insect repellant cannot help in the prevention of Giardia infection. Hence, the option (c) is not correct.
Cooking all food is not the effective prevention of Giardiasis. Giardiasis is waterborne disease. Cysts of this parasite can withstand boiling. In endemic areas, filtered water should be used for cooking and washing the utensils, which are used for eating. Hence, the option (d) is not correct. Hence, the correct option is (b) drinking only bottled water.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 18MC
The sporogenic phase of Plasmodium occurs in Anopheles mosquito. As the mosquito takes the blood meal from humans, it ingests gametocytes present inside the red blood cells. The gametocytes are released from the red blood cells in the digestive tract of mosquitoes and the gametes are formed. The zygotes are formed after the fertilization of female gametes by male gametes. The zygote changes into ookinete, which in turn changes into oocyst in the mosquitoes’ gut wall. This oocyst undergoes meiosis and releases thousands of sporozoites after the rupture of the cystic wall. These sporozoites enter the salivary glands of the mosquitoes. These are transmitted to a new host during the blood meal. Hence, the option (d) is correct.
The sporogenic phase of Plasmodium does not occur in red blood cells. It occurs in Anopheles mosquito. The erythrocytic cycle occurs in red blood cells. The merozoites which are free swimming in the blood circulation enter the erythrocytes. After entering inside the red blood cells, it changes into trophozoites. The trophozoites endocytize the hemoglobin protein present in the red blood cells. The diagnostic sign of malaria is the presence of trophozoites inside the red blood cells. More merozoites are produced from the trophozoites by schizogony. Merocytes destroy the erythrocytes and thus continues the life cycle. Hence, the option (a) is not correct.
Liver cells are not the site for sporogenic phase of Plasmodium. The infected female Anopheles mosquito injects sporozoites into the blood stream of humans. These sporozoites enter the liver and schizogony takes place inside the liver cells. Merozoites are produced as a result of schizogony. These merozoites rupture the liver cells and enter the blood circulation. Hence, the option (b) is not correct.
Schizonts contain merozoites. These are oval or round in shape. The sporogenic phase of Plasmodium does not occur in the schizonts. Hence, option (c) is not correct. Hence, the correct option is (d) Anopheles mosquito.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 19MC
The tapeworm attachment organ is scolex. It is a small organ having suckers and hooks. The main function of scolex is anchorage. The tapeworm gets attached to the tissues of the host by this scolex. It is the anterior end of tapeworm. Hence, the option (a) is correct.
Proglottid is not the attachment organ of tapeworm. Body segments are called proglottids. The neck is present behind scolex. Segments of the body are attached from the neck continuously. New proglottids displace the older ones away from the neck. When the proglottids get mature, male and female reproductive organs are produced in them. Proglottids are monoecious. The proglottids filled with eggs are often shed along the feces. Hence, the option (b) is not correct.
Strobila is not the organ for attachment in tapeworm. The body segments called proglottids look like a chain. This chain of proglottids is called strobila. The strobila shows the order of development. The proglottids present near the neck are immature and towards the middle of the chain are mature and the proglottids near the posterior end are gravid with fertilized eggs. Hence, the option (c) is not correct.
Cuticle is not the attachment organ of tape worm. Cuticle is the outer skin of the tapeworm. The nutrients are absorbed through the cuticle. There is not mouth for the tapeworm. Hence, the option (d) is not correct. Hence, the correct option is (a) scolex.

Microbiology with Diseases by Taxonomy Chapter 23 Answers 20MC
Trophozoite-cyst conversion is vital to the life of Balantidium, Entamoeba, and Giardia. In all these protozoans these two stages of life cycle is present. Trophozoites are released from the cystic wall after ingestion by the host. These trophozoites undergo encystment and form cysts, which are infective. Hence, the option (d) is correct.
In Balantidium, life cycle has two stages of development called trophozoite and cyst. Infection takes place by the ingestion of cysts. After reaching the small intestine trophozoites are produced. In the large intestine, the trophozoites are colonized and feed on the intestinal flora. Encystment takes place in the distal part of the large intestine or outside the body in feces. The trophozoite-cyst conversion is not only in Balantidium, but also in other protozoan parasites. Hence, the option (a) is not correct.
Entamoeba life cycle also has two stages. The trophozoites in the large intestine feed on bacterial flora and undergo binary fission. Encystation occurs. Cystic stage is formed which is used in the transmission of the parasite. The trophozoite-cyst conversion is not only in Entamoeba. Hence, the option (b) is not correct.
Giardia has two stages in its life cycle. They are active trophozoites and infective cyst. After the ingestion of cysts the trophozoites are released and remain in the lumen of small intestine. Then they move towards the large intestine where encystment takes place. The cysts are infective. There are other protozoans, which have trophozoite-cyst conversion in the life cycle. Hence, the option (c) is not correct. Therefore, the correct answer is option (d) all of the above.

Microbiology with Diseases by Taxonomy Chapter 21 Answers

Microbiology with Diseases by Taxonomy Chapter 21 Answers

Microbiology with Diseases by Taxonomy Answers

Microbiology with Diseases by Taxonomy Chapter 21 Answers 1CM
The following concept map describes the sexually transmitted disease syphilis. The causative organism, stages, diagnosis and treatment of syphilis are shown in this concept map.
microbiology-with-diseases-by-taxonomy-chapter-21-answers-1cm
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Microbiology with Diseases by Taxonomy Chapter 21 Answers 1CT
The arthropods like ticks transmit the diseases Rocky Mountain spotted fever and Lyme disease. These diseases are caused by the agents Rickettsia rickettsii and Borrelia burgdorferi respectively.
The treatment for these diseases includes the removal of the tick from the human body. Antimicrobial drugs are effective at the primary stage of the infection. As the disease progresses, they become ineffective because the later symptoms will result from the immune response. Vaccine is available, but it is not widely used as it may cause infection in some patients.
Prevention of the infection involves using tick repellents, tight fitting clothes and covering the body completely. The ticks cannot be eliminated completely as they can survive even for a period of four years without feeding.
Cholera is caused by consuming contaminated water. The causative organism is Vibrio cholerae. A high innoculum is required to cause the infection.
Treatment of cholera includes using antimicrobial drugs and replacing the fluid and electrolytes. A promising oral vaccine is available for cholera.
Prevention and limiting the spread of the disease can be attained by proper hygiene and adequate sewage and water treatment. This causative bacterium is sensitive to drying also. By using any of these, the disease can be controlled.
Thus, it is easy to control cholera than controlling RMSF and Lyme disease (as the ticks cannot be easily prevented).
Hence, it is difficult to rid a community of the disease transmitted by arthropods than that of a disease transmitted by contaminated water.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 1L
The following figure shows the stages and structures of the chlamydia life cycle. The time taken at each step has been indicated.
(6) Elementary body
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  1. The chlamydial life cycle starts with the attachment of the elementary body (EB) to the host cell.
  2. The EB will enter into the host cell by endocytosis.
  3. In the host cell, the EB will be converted into a reticulate body (RB). This will take about 10 hrs after infection.
  4. The RB will divide rapidly inside the cell. Due to this, more RBs will be produced.
  5. The endosome that is completely filled with RBs is called inclusion body.
  6. After 21 hrs of infection, the RBs present in the endosome will start converting into EBs.
  7. From that after 19 hrs, the EBs will be released from the host cell by exocytosis.
  8. Some of these EBs will infect new host cell. Again the chlamydial life cycle will start.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 1M

  1. Rocky Mountain spotted fever is a lethal illness, most frequently reported in USA (United States of America). This disease is caused by Rickettsia rickettsii. This bacterium is spread to human by Dermacentor ticks. Hence, this option matches with (C) Rickettsia rickettsii.
  2. Endemic typhus is a form of typhus, which is transmitted by fleas. This disease is caused by Rickettsia typhi. It is also called murine typhus. Hence, this option matches with (A) Rickettsia typhi.
  3. Epidemic typhus is a form of typhus often causes epidemics following natural disasters and wars. This disease is caused by Rickettsia prowazekii, and is transmitted by the human louse. Hence, this option matches with (B) Rickettsia prowazekii.
  4. Scrub typhus is a form of typhus caused by Orientiatsutsugamushi (an intracellular parasite). This bacterium belongs to the family Rickettsiaceae. This disease is transmitted by some species of trombiculid mites. Hence, this option matches with (D) Orientiatsutsugamushi.
  5. Human monocyticehrlichiosis (HME) is a form of ehrlichiosis, and is caused by Ehrlichiachaffeensis. This bacterium is an obligate intracellular pathogen that affects macrophages and monocytes. Hence, this option matches with (E) Ehrlichiachaffeensis.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 1MC
Most human infections caused by species of Rickettsia are transmitted through vectors.
(a) Are acquired from fomites:
Fomites like toilet seats, utensils, or clothing cannot transmit the infections caused by Rickettsia. These infections are transmitted by arthropod vectors. Hence, this option is incorrect.
(b) Could be prevented by hand washing:
These human infections cannot be prevented by washing hands. As they are transmitted by vectors like ticks, lice and fleas, they can only prevented by avoiding the vectors. Hence, this option is incorrect.
(c) Are transmitted via vectors:
The infections caused by Rickettsia are transmitted through arthropod vectors. Rocky mountain spotted fever is transmitted by hard ticks. Typhus is transmitted either by human body louse or rat fleas. Hence, this option is correct.
(d) Are sexually transmitted:
The infections caused by Rickettsia are transmitted alone by arthropod vectors. There is no other means for their transmission. Hence, this option is incorrect.
Hence, the correct option is (c) are transmitted via vectors. Most human infections caused by Rickettsia are transmitted through arthropod vectors.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 1SA
Rickettsias have functional genes for protein synthesis, ATP production and reproduction. In such a condition also, they are obligate parasites. To explain this, scientists have proposed several hypotheses.
Obligate parasites are those organisms that complete their life cycles without exploiting a host.
The primary hypothesis is:

  • Rickettsias have very leaky cytoplasmic membranes. Due to this, they should lose their cofactors. But, they lose even the small cofactors like NAD+, only when they are in a particular environment. That environment should contain equivalent amount of these cofactors. Example for such an environment is cytosol of a cell.
  • This hypothesis explains that rickettsias are obligate parasites. That means they require a host cell for the completion of their life cycle.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 2CT
Following are the two primary theories that attempt to find the origin of syphilis.

  • According to Columbian theory New World disease syphilis was brought back to Europe by homecoming Spanish explorers – Columbus and Martin Alonso Pinzon. Columbus’s voyages to the Americas took place three years prior to Naples syphilis outbreak of 1494. The Columbian theory is sustained by genetic funding of venereal syphilis and associated bacteria, which found a disease midway between syphilis and yaws in Guyana, South America.
  • According to pre-Columbian theory syphilis was present in Europe even prior to the arrival of Europeans in the Americas. In 18th and 19th centuries some scholars believed that the signs of syphilis in its tertiary stage were pronounced by Hippocrates in Classical Greece. However, these claims were not presented for peer review, and the evidence provided to other scientists were not strong enough. According to Douglas W. Owsley many medieval European cases of leprosy, were in actual cases of syphilis. Although it is claimed that syphilis was present in Europe till the homecoming of the diseased sailors of the Columbian voyages, Owsley states that “syphilis probably cannot be “blamed”— on any specific race or geographical area.
  • The evidence indicates that syphilis existent in both hemispheres through the prehistoric times. However, it is only by fluke that the Columbus expeditions coincided with the “lepra” that spread into virulence by end of the 15th century.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 2M

  1. Rickettsia typhi is transmitted to humans by the vectors rat flea Xenopsylla cheopis and cat flea Ctenocephalides felis. Hence, the correct option is (A) Rat flea.
  2. Rickettsia prowazekii is transmitted by human body louse, Pediculis humanus.Hence, the correct option is (B) Body louse.
  3. Rickettsia rickettsii is transmitted by hard ticks of the genus Dermacentor. Hence, the correct option is (C) Hard tick.
  4. Orientia tsutsugamushi is transmitted by the mites of the genus Leptotrombidium. Hence, the correct option is (D) Mite.
  5. Ehrlichia chaffeensis is transmitted by the hard ticks like Lone Star tick, deer tick and the dog tick. Hence, the correct option is (C) Hard tick.
  6. Borrelia burgdorferi is transmitted by the hard ticks of the genus Ixodes. Hence, the correct option is (C) Hard tick.
  7. Borrelia recurrentis is transmitted by the human body louse Pediculus humanus and by the soft ticks of the genus Ornithodoros. Hence, the correct options are (B) Body louse and (E) Soft tick.
  8. Anaplasma phagocytophilum is transmitted by the hard ticks like Lone Star tick, deer tick and the dog tick. Hence, the correct option is (C) Hard tick.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 2MC
The bacterium that causes RMSF is more likely to infect a human when an infected tick feeds for several hours. The bacterium is Rickettsia rickettsii.
(a) If an infected tick feeds for several hours:
Rocky Mountain spotted fever is transmitted through the vector hard ticks. It is transmitted only when the tick feeds the human blood for several hours. In such a condition only, the bacterium gets activated. Hence, this option is correct.
(b) When an infected tick initially penetrates the skin:
The bacterium that causes RMSF gets activated only when the tick feeds on the human blood for several hours. When the tick initially penetrates the skin, the bacterium will be inactive. Thus there will be no chance of infection. Hence, this option is incorrect.
(c) When contaminated tick feces dry and become airborne:
The humans can be infected with RMSF, when they are exposed to the tissues and fluids of crushed ticks or to ticks’ feces. This happens very rarely. But, the infection is never airborne. Hence, this option is incorrect.
(d) If the human is exposed to rodent feces containing the bacterium:
RMSF is transmitted to humans and rodents through hard ticks. In very cases, it is transmitted through crushed ticks or ticks’ feces. It cannot be transmitted through rodent feces, as the bacterium if present in it becomes inactive. Hence, this option is incorrect.
Hence, the correct option is (a) if an infected tick feeds for several hours. The bacterium that causes RMSF is more likely to infect a human when an infected tick feeds for several hours.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 2SA
The bacteria Ehrlichia and Anaplasma are transmitted to the humans by ticks. They enter the blood stream of humans. The bacteria will trigger their own phagocytosis. The phagocytosis is by a white blood cell. That may be either a monocyte or a neutrophil. These bacteria grow and reproduce inside the host cell.
If this phagocytic cell fuses with a lysosome, then there will be a chance of killing the bacteria. Thus, the bacteria will inhibit the fusing of phagosome with the lysosome.
The bacteria undergo three developmental stages inside the phagosome. Once the bacteria enter into the host cell phagosome, it will be called an elementary body. It will contain the host cell wall as its covering. These bodies grow and develop into initial bodies. After reproduction, morula will be formed. It will contain a number of bacterial cells, which are produced due to reproduction. The morula will fuse with the host cellwall. Due to this, the bacterial cells will be released into the blood. By this, they are made available to the feeding ticks.
By feeding such an infected blood, the ticks will transmit the bacteria to another individual.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 3CT
The bacterium responsible for the man’s death might be Vibrio vulnificus.
Vibrio vulnificus is Gram-negative, curved bacilli. They are transmitted by eating raw or uncooked as well as contaminated sea food. They also attack the humans while washing the open wounds with sea water. They are responsible for septicemia.
The symptoms of the infection include vomiting, diarrhea, abdominal pain and blistering skin. As the infection progresses, septic shock and even death may occur. This bacterium is fatal for 50% of untreated patients.
The patient was suffering with severe abdominal pain, diarrhea and fell into coma. After a week, he died. It is known that the patient had sea urchins before he was ill. By this information, it seems that the sea urchins are contaminated with Vibrio vulnificus. This bacterium infected the patient and led him to coma and even death.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 3M

  1. Chlamydophila psittaci is a bacterial species that causes ornithosis. It is a bird disease transmitted to the humans. Potential hosts include feral birds, pigs, cattle, sheep etc. Chlamydophila psittaci is transmitter thorough contact, or inhalation. Hence, this option matches with (G) Ornithosis.
  2. Chlamydophila pneumoniae is an obligate intracellular pathogen that causes pneumonia, bronchitis and sinusitis in humans. These pathogens have very complex life cycle, as the name indicating they require a host to reproduce. Hence, this option matches with (C) Sinusitis.
  3. Chlamydia trachomatis causes sexually transmitted disease called as lymphogranuloma venereum. It also causes ocular disease called trachoma. Besides these, it also causes proctitis and pelvic inflammatory disease. Hence, this option matches with (B) Trachoma, (D) Lymphogranuloma venereum, (E)Proctitis and (F) Pelvic inflammatory disease.
  4. Treponema pallidum pallidum belongs to spirochaete bacteria that cause syphilis, which is a sexually transmitted disease. These bacteria have an outer membrane and cytoplasmic membrane. Hence, this option matches with (A) Syphilis.
  5. Treponema pallidum pertenue causes yaws, which is characterized by granular lesions. This infection is a tropical infection of the bones, skin and joints. Hence, this option matches with (H) Yaws.
  6. Treponema pallidum endemicum causes bejel, which is seen in children. This disease is a chronic tissue and skin disease. This disease is also known as dichuchwa, frenga, skerljevo, belesh etc. Hence, this option matches with (I) Bejel.
  7. Treponema carateum causes a skin disease called pinta. It is human skin disease that is endemic to Central America, Mexico, and South America. Hence, this option matches with (J) Pinta.
  8. Borrelia burgdorferi belongs to spirochets bacterium, class of the genus Borrelia. It is gram negative bacteria that cause Lyme disease. It is characterized mainly by arthritis. Hence, this option matches with (K) Lyme disease.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 3MC
(a) Rickettsia typhi:
It causes murine typhus. It is usually not fatal. It is not severe. It is transmitted to humans by the vectors rat flea Xenopsylla cheopis and cat flea Ctenocephalides felis. Hence, this option is incorrect.
(b) Rickettsia rickettsii:
It causes Rocky Mountain spotted fever (RMSF). This infection is the most severe and most reported of all the rickettsial infections. Hence, this option is correct.
(c) Orientia tsutsugamushi:
It causes scrub typhus. This infection is endemic. In a very few cases death results due to heart failure. It is not very severe. Hence, this option is incorrect.
(d) Ehrlichia chaffeensis:
It causes human monocytic ehrlichiosis. Only 5% of the cases result in death, if the infection is left untreated. It is not severe as that of RMSF. Hence, this option is incorrect.
Hence, the correct option is (b) Rickettsia rickettsii. The most severe rickettsial infection is caused by Rickettsia rickettsii.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 3SA
Scientists faced problems in identifying the virulence factors of T. pallidum pallidum because the pathogen cannot be cultured. So, the scientists are not able to work out on the pathogen in vitro conditions.
To make it grow in vitro, they used recombinant DNA technology. By this, they inserted the genes of Treponema into E.coli. This made the pathogen to be cultured. Then, they isolated the genes and their respective proteins. After this, the virulence factors of the pathogen are identified.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 4CT
Heliobacter pylori is a urease positive enzyme. Urease degrades urea. Urea is present in the gastric juice. Urea after degradation, it forms into very alkaline ammonia. This ammonia neutralizes the stomach acid. By this, the bacterium gets the access to enter the underlying epithelial cells. Then, the epithelial tissue will be ulcerated. After that, the muscle tissue and blood vessels will be attacked by the bacterium. This is the formation of peptic ulcers.
The mutated Heliobacter pylori is urease negative. So, it cannot degrade urea and produce alkaline condition in the stomach. As and when this mutated bacterium enters the stomach, it gets degraded by the acid in the stomach. Hence, it cannot form peptic ulcers in normal conditions.
This strain causes peptic ulcers only in some patients. In those patients, who consume antacids in large amounts or use drugs to block acid production in the stomach. These drugs decrease the amount of acid in the stomach. Thus, this is an alkaline condition, which favours the bacterium. The mutated bacterium will not be damaged. Hence, this leads to the formation of peptic ulcers in the patients who consume antacids or drugs to block the production of acid.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 4M

  1. Peptic ulcers are the erosions of the mucus membrane in the stomach and small intestine. These are caused by the bacterium Heliobacter pylori. Hence, the option matches with (E) Heliobacter pylori.
  2. Gastroenteritis is mostly caused by Campylobacter jejuni. Cholera like gastroenteritis is caused by Vibrio parahaemolyticus. Gastritis is caused by Heliobacter pylori. Hence, the option matches with (B) Vibrio parahaemolyticus (D) Campylobacter jejuni and (E) Heliobacter pylori.
  3. Blood poisoning is called septicemia. Septicemia is the condition in which there is a presence of microbes or their toxic products in the blood. It is caused by Vibrio vulnificus. Hence, the option matches with (C) Vibrio vulnificus.
  4. Cholera is an infection that affects the small intestine caused by Vibrio cholerae. The main symptoms are vomitings and diarrhea. This disease is transmitted primarily by drinking contaminated water or consuming food that is contaminated by the feces. Hence, the option matches with (A) Vibrio cholerae.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 4MC
(a) Rickettsias:
This is genus of nonmotile, non-sporeforming, gram-negative cocci that are obligate intracellular parasites. These are tiny, Gram-negative, obligate, intracellular parasites that live in the cytosol of host cells. Hence, this option is correct.
(b) Mycoplasmas:
These belong to genus of bacteria that lack cell walls. These are small cells, acellular, and free living organisms. Hence, this option is incorrect.
(c) Chlamydias:
These belong to genus of bacteria that are obligate intracellular parasites. These are small, obligate, intracellular parasites that live in endosomes. Hence, this option is correct.
(d) Both a and c:
As the options a and c are correct, this option is correct. Hence, the correct option is (d) both a and c. The smallest cellular microbes are rickettsias and chlamydias.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 4SA
The causative agent of syphilis is Treponema pallidum pallidum. Untreated syphilis has four phases. They are:

  1. Primary phase,
  2. Secondary phase,
  3. Latent phase and
  4. Tertiary phase.

In primary syphilis, a small, painless and red colored lesion forms at the site of infection. These lesions are called as chancres. They form in the mouth, around the anus, or on the fingers, lips, nipples, or on the cervix. The center of the chancre will be filled with serum. This serum is very infectious. After three to six weeks, the lesions will disappear. In most of the cases, this will be the end of the disease.
The secondary syphilis starts with the invasion of Treponema into the blood stream. Due to this, the infection spreads all over the body. The symptoms will be sore throat, headache, mild fever, malaise, myalgia, lymphadenopathy and rash. The rash includes the palms and the soles of the feet also. The lesions of this rash will be very infectious. This rash disappears after several weeks or months.
Latent syphilis is clinically inactive. This phase lasts upto 30 or more years. In many cases, the disease will not advance beyond this phase.
Teritiary syphilis is not directly associated with the effects of Treponema. This phase comprises of severe complications, which result from inflammation and hyperimmune response against the pathogen. Any tissue or organ can be affected. This causes dementia, blindness, paralysis, heart failure and syphilitic lesions. These lesions are called as gummas. These are rubbery, painful and swollen lesions that occur in bones, nervous tissue or on the skin.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 5CT
The symptoms of the infection are headache, myalgia and recurring fever. Each fever is last for three days. All the members of the family are infected. This outbreak occurred after the gathering in a remote area. These characteristics say that this disease relapsing fever.
Relapsing fever is caused by Borrelia recurrentis. This is transmitted by either ticks or lice. Hence, the relapsing fever is of two types. They are tick-borne relapsing fever and louse-borne relapsing fever. Both of these have the same symptoms.
Relapsing fever is successfully treated with doxycycline. It is treated with erythromycin in pregnant women and children.
Prevention of relapsing fever involves the avoidance of lice and ticks, use of repellent creams and maintaining good personal hygiene.
The family could be protected itself by maintaining proper hygiene and by taking proper treatment.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 5MC
The most commonly reported sexually transmitted disease in United States is caused by the bacterium Chlamydia trachomatis.
(a) Mycoplasma genitalium :
It is a sexually transmitted disease. It attacks the genital and respiratory tracts. The symptoms are urethritis, arthritis and so on. It may cause pelvic inflammatory disease. This is not a most prevalent disease in United States. Hence, this option is incorrect.
(b) Chlamydia trachomatis :
It is sexually transmitted to result in chlamydial infection. It is the most commonly reported sexually transmitted disease in United States. 1,093,514 cases are reported in 2008. Hence, this option is correct.
(c) Chlamyophila proctitis : This option is not applicable.
(d) Ureaplasma urealyticum :
It is a sexually transmitted. It is associated with urethritis, infertility, premature birth, pneumonia and meningitis. It is not more prevalent in United States. Hence, this option is incorrect.
Hence, the correct option is (b) Chlamydia trachomatis. The most commonly reported sexually transmitted disease in the United States is caused by the bacterium Chlamydia trachomatis.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 5SA
Leptospirosis is caused by Leptospira interrogans. This disease normally occurs in many wild and domestic animals and humans. It is a zoonotic disease. It occurs throughout the world and it is not fatal.
The spread of Leptospira can be controlled in the best way by rodent control. Various rodent control methods can be used to control this disease.
The eradication of this pathogen is impractical, as animals are the reservoirs for this pathogen. An effective vaccine is available for livestock and pets.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 6MC
The disease that is least likely in rural areas of United States is epidemic typhus.
(a) Epidemic typhus:
This infection is caused by Rickettsia prowazekii. It is widely prevalent all around the world. But, it is endemic in Central and South America. Thus, it is found rarely in rural areas of United States. Hence, this option is correct.
(b) Rocky Mountain spotted fever:
It is caused by Rickettsia rickettsii. It is more prevalent in the Appalachian Mountains, Oklahoma, and the southeastern states. Thus, this fever is more prevalent in United States. Hence, this option is incorrect.
(c) Murine typhus:
It is caused by Rickettsia typhi. It is also known as endemic typhus. It is most often seen in the southern United States. Hence, this option is incorrect.
(d) Lymphogranuloma venereum:
It is a sexually transmitted disease caused by Chlamydia trachomatis. It is the most commonly transmitted in the United States. Hence, this option is incorrect.
Hence, the correct option is (a) epidemic typhus. The disease that is least likely in rural areas of the United States is epidemic typhus.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 6SA
V.cholerae O1 E1 Tor causes cholera. It is one of the world’s pernicious diseases.
The humans become infected by the ingestion of contaminated water and food. After entering the digestive system, most of the cells die. This results due to the acidic environment of the stomach. Hence, a high inoculum is required for the disease to develop.
Cholera infections are asymptomatic or cause mild diarrhea. But, some infections result in rapid, severe and fatal fluid. It causes electrolyte lose. The symptoms watery diarrhea and vomiting begin after two to three days of infection. As the days go on, the colon becomes emptied and the stool becomes more watery, colorless and odorless. The stool containing mucus is called rice-water stool.
Some patients may even lose 1 liter of fluid per an hour. Dehydration takes place due to severe fluid and electrolyte lose. Besides this, acidosis, hypokalemia and hypovolemic shocks are caused. These conditions may result in muscle cramping, irregularities in heartbeat, kidney failure, coma and death.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 7MC
Treatment of chlamydial infections involves erythromycin and doxycycline creams as well as surgical correction of eyelid deformities.
The best example of a chlamydial infection is trachoma. It is an eye disease caused by Chlamydia trachomatis.
(a) Erythromycin cream:
Some strains of Chlamydia trachomatis infect the eyes of newborns. This infection is treated with erythromycin cream for 10 to 14 days. Hence, this option is correct.
(b) Doxycycline cream:
Eye infections in adults are caused by the lyphogranuloma venereum strains of C.trachomatis. Such infections are treated with doxycycline cream for 7 days. Hence, this option is correct.
(c) Surgical correction of eyelid deformities:
The abrasion, scaring, and blindness that resulted from ocular infections can be prevented by surgical correction of eyelid deformities. Hence, this option is correct.
(d) All of the above:
As the options (a), (b) and (c) are correct, this option is correct.
Hence, the correct option is (d) all of the above. Treatment of chlamydial infections involve erythromycin cream, doxycycline cream and surgical correction of eyelid deformities.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 8MC
The organism that is transmitted via sexual contact is Treponema pallidum pallidum.
(a) Treponema pallidum endemicum :
It causes the disease bejel. It is transmitted through contaminated utensils. It is a nonvenereal disease. Hence, this option is incorrect.
(b) Treponema pallidum pertenue :
It causes yaws. It is transmitted when the persons come in contact with the fluid that is coming out of the lesions. It is a nonvenereal disease. Hence, this option is incorrect.
(c) Treponema pallidum pallidum :
It causes syphilis. It is transmitted through sexual contact. So, it is a venereal disease. Hence, this option is correct.
(d) Treponema carateum :
It causes pinta. It spreads among children by skin-to-skin contact. It is a nonvenereal disease. Hence, this option is incorrect.
Hence, the correct option is (c) Treponema pallidum pallidum. The organism that is transmitted via sexual contact is Treponema pallidum pallidum.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 9MC
There is no effective vaccine for cholera.
(a) The causative agent lives naturally in marine water:
The causative agent of cholera is Vibrio cholera. This lives naturally in estuarine and marine waters. This is worldwide in distribution. Hence, this option is true about cholera.
(b) There is an effective vaccine for cholera:
A new oral vaccine has been developed for O1 strain of V.cholerae. There is no vaccine for O139 strain. Research is going on for the development of vaccine for cholera. Hence, this option is false about cholera.
(c) Strain O1 E1 Tor has been responsible for several pandemics:
The seventh pandemic began due to the strain O1 E1 Tor. This started in Asia and later spreaded to Africa and Europe. This reached Peru also. Recently, strain O139 was found to be arosing pandemic. No other strain is responsible for pandemics. Hence, this option is true about cholera.
(d) Rice-water stool is a symptom:
As cholera progresses, the stool will be completely filled with mucus. It resembles the water that is poured out from boiled rice. Thus, it is called as rice- water stool. Hence, this option is true about cholera.
Hence, the correct option is (b) there is an effective vaccine for cholera, which is not true of cholera.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 10MC
Penicillin is ineffective at the tertiary stage of syphilis.
(a) Primary syphilis:
After 10-21 days of infection, a reddened lesion called chancre forms. The serum from this lesion will be infectious. This will disappear after three to six weeks. At this stage, penicillin is effective. Hence, this option is incorrect.
(b) Secondary syphilis:
At this stage, a widespread rash that includes even the palms and soles of feet will be formed. The lesions of this rash are infectious. At this stage, penicillin is effective. Hence, this option is incorrect.
(c) Tertiary syphilis:
At this stage, rubbery, painful and swollen lesions called gummas will be formed. This stage may result in heart failure. At this stage, penicillin is ineffective. Hence, this option is correct.
(d) All of the above:
As the options (a) and (b) are incorrect, this option is incorrect.
Hence, the correct option is (c) tertiary syphilis. Penicillin is ineffective during tertiary syphilis.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 11MC
Two weeks after a backpacking trip in Tennessee, a hiker experienced flulike symptoms and noticed a red rash on his thigh. The likely cause of this illness is Borrelia burgdorferi.
(a) Treponema pallidum pertenue :
It causes yaws. It forms large, destructive and draining lesions. These lesions will be formed on the skin, bones and lymphnodes. Hence, this option is incorrect.
(b) Borrelia burgdorferi :
It causes lyme disease. It is characterized by a red rash at the site of infection. The symptoms include malaise, fatigue, fever, chills, pains and lymphadenopathy. These are flulike symptoms. Hence, this option is correct.
(c) Borrelia recurrentis :
It causes relapsing fever. It is characterized by recurrent episodes of septicemia and fever. These episodes are separated by symptom free intervals. No lesions will be formed. Hence, this option is incorrect.
(d) Leptospira interrogans :
It causes leptospirosis. It is a zoonotic infection. The bacterium travels all over the human body through the bloodstream. The mucus lining of the blood vessels get damaged. This results in pain and fever. This may lead to dysfunction of liver and kidney. Hence, this option is incorrect.
Hence, the correct option is (b) Borrelia burgdorferi. It causes an infection that is characterized by a red rash and flulike symptoms.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 12MC
The most common cause of bacterial gastroenteritis in the United States is Campylobacter jejuni.
(a) Vibrio parahaemolyticus :
It causes cholera like gastroenteritis. It is due to the intake of shellfish grown in contaminated water. Rarely, it is severe leading to death. It is not the common cause for gastroenteritis. Hence, this option is incorrect.
(b) Campylobacter jejuni :
It is the most common cause of bacterial gastroenteritis in the United States. The infection is zoonotic. Hence, this option is correct.
(c) Helicobacter pylori :
It causes gastritis and most peptic ulcers. It is not the common cause for gastroenteritis. Hence, this option is incorrect.
(d) Vibrio cholerae :
It causes cholera. This is one of the world’s more pernicious diseases. It does not cause gastroenteritis. Hence, this option is incorrect.
Hence, the correct option is (b) Campylobacter jejuni. The most common cause of bacterial gastroenteritis in United States is Campylobacter jejuni.

Microbiology with Diseases by Taxonomy Chapter 21 Answers 13MC
The disease that forms lesions called gummas is syphilis.
(a) Ornithosis:
This disease is caused by Chlamydophila psittaci. It is a disease of birds that can be transmitted to humans. It causes flu like symptoms. It does not form any lesion. Hence, this option is incorrect.
(b) Syphilis:
It is a sexually transmitted disease. It is caused by Treponema pallidum pallidum. It forms lesions in all stages of the disease. The lesions formed in the tertiary stage of syphilis are called as gummas. They are rubbery, painful and swollen lesions. These lesions occur in bones, nervous tissue or on the skin. Hence, this option is correct.
(c) Trachoma:
It is an eye disease. It is caused by Chlamydia trachomatis. It does not form any lesions. Hence, this option is incorrect.
(d) Pneumonia:
The symptoms for pneumonia are cough, fever, fast breathing, fast heartbeat, nausea, pains and so on. But it does not form any lesions. Hence, this option is incorrect.
Hence, the correct option is (b) syphilis. The disease that causes gummas is syphilis.