Deck 24: Digestive System Infections

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Question
The chronic inflammatory process involving the gums and tissues around the teeth is called

A)dental caries.
B)periodontal disease.
C)dental plaque.
D)root caries.
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Question
The viral disease that characteristically infects the parotid glands is

A)measles.
B)herpes.
C)chickenpox.
D)mumps.
Question
The diarrhea of cholera has been described as

A)a viscous fluid.
B)small in volume.
C)somewhat watery.
D)a rice water stool.
Question
Where in the body does the latent, non-infectious, non-replicating form of the herpes simplex virus persist?

A)motor neurons
B)red blood cells
C)cranial nerves
D)sensory nerves
Question
The most common infectious disease of humans is
A)

A)the common cold.
B)dental caries.
C)hepatitis
D)halitosis
Question
This mineral, typically added to drinking water, makes enamel more resistant to dissolving in acid.

A)calcium
B)chlorine
C)chloramine
D)fluoride
Question
The initial attachment required for establishment of an intestinal infection is by

A)flagella.
B)cilia.
C)pseudopodia.
D)pili.
Question
The principal cause of dental caries is

A)S.mutans.
B)S.salivarius.
C)S.mitis.
D)S.sanguis.
Question
Who determined that the cholera outbreak in 1850s London was due to contaminated water and approached the problem by removing the pump handle at the contaminated site?

A)Pasteur
B)Snow
C)Koch
D)Smith
Question
H. pylori appears to have some connection with

A)acid reflux disease.
B)ulcers.
C)dental caries.
D)stomach cancer.
E)ulcers AND stomach cancer.
Question
The passage from the mouth to the anus is termed the

A)gut canal.
B)oral cavity.
C)grand canal.
D)alimentary canal.
Question
Cholera is the classic example of a(n)

A)food-borne illness.
B)zoonosis.
C)opportunist.
D)very severe form of diarrhea.
Question
A painful finger infection attributable to herpes virus is known as a(n)

A)finger sore.
B)abrasion lesion.
C)furuncle.
D)herpetic whitlow.
Question
Collections of bacteria that adhere to the surfaces of the teeth are called

A)dental caries.
B)dental plaque.
C)halitosis.
D)periodontal disease.
Question
Part of the ability of S. mutans to produce dental caries depends on its ability to

A)invade plaque and dissolve the gums.
B)convert sucrose to lactic acid.
C)convert proteins to sugars.
D)attach to the gums.
Question
Which of the following has shown some effectiveness in treating a herpes infection?

A)AZT
B)protease inhibitors
C)acyclovir
D)cephalosporin
Question
The toxins involved in intestinal infections typically

A)kill cells by inhibiting protein synthesis.
B)modify cell physiology resulting in increased secretion of water and electrolytes.
C)modify cell physiology resulting in decreased secretion of water and electrolytes.
D)kill cells by inhibiting DNA synthesis.
E)kill cells by inhibiting protein synthesis AND modify cell physiology resulting in increased secretion of water and electrolytes.
Question
Mumps is a good candidate for elimination from the population due to

A)the existence of an effective vaccine.
B)a human only reservoir.
C)the absence of a latent state.
D)a single serotype.
E)All of the choices are correct.
Question
H. pylori is, in part, able to survive in the stomach by its ability to produce

A)lactic acid from sugar.
B)fatty acids from sebum.
C)neutralizing proteins from glucans.
D)ammonia from urea.
Question
The symptoms of cholera are due to the action of

A)an endotoxin.
B)modified mucus.
C)flagella.
D)an exotoxin.
Question
The food products most commonly contaminated with Salmonella strains are

A)meat and seafood.
B)milk and cheese.
C)fruit and vegetables.
D)eggs and poultry.
Question
Which of the following groups give rise to a disease similar to that caused by Shigella sp.?

A)enterotoxigenic
B)enteroinvasive
C)enteropathogenic
D)enterohemorrhagic
E)All of the choices are correct.
Question
Shigella

A)are themselves nonmotile.
B)may be pushed from cell to cell by actin tails.
C)utilize pili to move.
D)utilize flagella to move.
E)are themselves nonmotile AND may be pushed from cell to cell by actin tails.
Question
Viral gastroenteritis that affects people of all ages and usually lasts less than 3 days is caused by

A)herpes.
B)
B)hepatitis
C)norovirus.
D)rotavirus.
Question
V. cholera and most salmonellas are

A)killed by acid conditions.
B)stimulated by acid conditions.
C)killed by low concentrations of salt.
D)killed by neutral conditions.
Question
Which group produces a toxin somewhat similar to that produced by Shigella dysenteriae?

A)enterotoxigenic
B)enteroinvasive
C)enteropathogenic
D)enterohemorrhagic
E)All of the choices are correct.
Question
A mysterious sequel to

A)Reye's syndrome.
B)Tourette's syndrome.
C)Pasteur's syndrome.
C)jejuni infections is
D)Guillain-Barré syndrome.
Question
The most notorious typhoid carrier was

A)Typhoid Tilly.
B)Typhoid Tom.
C)Typhoid Mary.
D)Typhoid Mark.
Question
In which of these organs does a carrier of typhoid bacilli maintain the bacteria?

A)liver
B)gallbladder
C)Peyer's patches
D)colon
E)liver AND Peyer's patches
Question
The animal(s) often associated with Salmonella strains is/are

A)turtles.
B)iguanas.
C)baby chickens.
D)ducks.
E)All of the choices are correct.
Question
Hepatitis A spreads via

A)the respiratory route.
B)blood transfusion.
C)body fluids.
D)the fecal-oral route.
Question
Shigella and cholera toxin both

A)have an A-B arrangement.
B)work through ADP ribosylation.
C)increase cAMP levels.
D)prevent protein synthesis.
Question
Protozoan infections are typically spread by

A)the respiratory route.
B)blood transfusion.
C)body fluids.
D)the fecal-oral route.
Question
HBV is mainly spread by

A)blood.
B)blood products.
C)semen.
D)saliva.
E)blood, blood products AND semen.
Question
Viral gastroenteritis in infants and children is most commonly caused by

A)herpes.
B)
B)hepatitis
C)Norwalk virus.
D)rotavirus.
Question
A common source of cholera infection is

A)acid rain.
B)unpasteurized milk.
C)fecal contaminated material, especially water.
D)boiled water.
E)acid rain AND boiled water.
Question
The primary treatment for cholera is

A)the administration of antibiotics.
B)vaccination.
C)by blood transfusion.
D)simply rehydration.
E)vaccination AND by blood transfusion.
Question
Most cases of Salmonella gastroenteritis have a(n)

A)water source.
B)human source.
C)plant source.
D)animal source.
Question
The most common chronic blood-borne infection in the U.S. is

A)hepatitis A
B)hepatitis B
C)hepatitis C
D)hepatitis D
Question
The most commonly identified waterborne illness in the United States is

A)amoebiasis.
B)cryptosporidiosis.
C)balantidiasis.
D)giardiasis.
Question
Cyclospora cayetanensis has, so far, not been identified with an animal source.
Question
H. pylori appears connected to stomach cancer and ulcers.
Question
The mumps virus initially infects the respiratory tract.
Question
Sucrose is one of the major contributors to the development of dental caries.
Question
Most North American outbreaks of Cyclospora cayetanensis have been associated with

A)cattle.
B)iguanas.
C)imported leafy vegetables and berries, especially raspberries.
D)chickens.
Question
Cyclosporiosis is transmissable from person to person.
Question
The infectious dose of cholera is much larger than that for Shigella.
Question
C. parvum may infect

A)dogs.
B)pigs.
C)cattle.
D)humans.
E)All of the choices are correct.
Question
The oocytes of Cyclospora cayetanensis

A)are mature when eliminated in the stool.
B)do not contain sporozoites when passed in the feces.
C)are smaller than the oocytes of Cryptosporidium parvum.
D)give rise to three sporozoites.
E)All of the choices are correct.
Question
Why might it be more difficult to prepare a vaccine against noroviruses than against rotaviruses?

A)We haven't been able to culture noroviruses in a lab setting yet.Without a starting culture, we can't create a vaccine.
B)Noroviruses are RNA viruses, where rotaviruses are DNA viruses.RNA viruses mutate far more easily than DNA viruses, so we COULD make a vaccine, but it would be rendered useless fairly quickly as the virus mutates.
C)We lack a proper culturing method for large-scale production of target cells for norovirus, whereas we have such a system for the target cells of rotaviruses.Without a system to get large numbers of target cells, we can't produce a vaccine.
D)Norovirus is much more infectious than rotavirus.As such, it's much harder to work with safety.This makes production of a vaccine too dangerous and unpredictable.
Question
Why would you expect acyclovir to be ineffective against latent HSV infections?

A)This is an antibacterial drug, and HSV is a virus.
B)This is an antifungal drug, and HSV is a virus.
C)This drug directly inhibits DNA polymerase activity-cells that are latently infected with HSV have no DNA polymerase activity.
D)This drug is a nucleoside analogue-it becomes activated by a viral enzyme that is produced only when the virus is replicating.As such, if the virus is latent, the enzyme to activate the drug is not present (and the drug is ineffective).
Question
Virulent strains of shigella typically carry a large plasmid.
Question
Both Giardia and
C.parvum are resistant to chlorine.
Question
Giardiasis may be contracted from

A)another person.
B)clear mountain streams.
C)chlorinated city water.
D)cold filtered beer.
E)another person, clear mountain streams AND chlorinated city water.
Question
Explain how Vibrio cholerae causes cholera without apparent damage to the intestinal epithelium.

A)This microbe causes destruction of the cellular structures underneath the intestinal epithelium-this is what induces the watery rice-stool characteristic of the illness.This leaves the overlying intestinal epithelium intact.
B)This microbe directly invades the intestinal epithelial cells, but does not kill them.Instead, while multiplying inside them, it causes them to secrete large amounts of chloride ions.This induces water to follow by osmosis, resulting in the watery rice-stool characteristic of the illness.
C)This microbe attaches to the surface of intestinal epithelial cells, secreting an exotoxin that causes the epithelium to secrete large amounts of chloride ions.This induces large amounts of water to follow by osmosis, resulting in the watery rice-stool characteristic of the illness.
D)The inflammatory reaction to the presence of this microbe causes the watery rice-stool characteristic of the illness.Therefore, it's technically the immune response that initiates the disease, although this response is induced by the presence of the microbe on the intestinal epithelium.
Question
The bacteria primarily responsible for dental caries is Streptococcus mutans.
Question
Would you expect an individual with giardiasis who has diarrhea to be more likely to transmit the disease than an individual with giardiasis who does NOT have diarrhea? Why or why not?

A)No-this illness is spread by respiratory droplets, so diarrhea as a symptom shouldn't matter for transmission of the disease.
B)No-this illness is spread by sexual contact, so diarrhea as a symptom shouldn't matter for transmission of the disease.
C)Yes-this illness is spread by the fecal-oral route, so presence of diarrhea as a symptom should dramatically increase the possibility of transmission of infection.
D)Yes-this illness is spread by insects that feed on contaminated fecal matter, becoming infected themselves.The disease is spread to new individuals when these infected insects bite a susceptible person, transmitting the cysts of the protozoan.As such, diarrhea as a symptom would increase the risk of transmission through biting insects to new individuals.
Question
The saliva of asymptomatic carriers of herpes simplex is commonly infectious.
Question
Why is it that the tongue and cheek epithelium doesn't provide a sufficient anaerobic environment for plaque anaerobes to grow, but the surface of teeth might?

A)The epithelium is supplied with oxygen by capillary beds.This makes it a relatively aerobic environment and hostile to anaerobes.
B)The tooth enamel is supplied with oxygen by capillary beds.This makes it a relatively anaerobic environment and hostile to aerobes.
C)The surface of the tongue and cheek are constantly scraped by the action of consuming food.Layers of bacterial growth that might help to supply an anaerobic environment are scraped away, exposing lower levels to oxygen-rich air.
D)The surface of teeth (especially the molars) have many pits and crevices that can serve as 'pockets' for layers of bacteria to grow in.Once the layers get deep enough, the bottom portions are anaerobic.This isn't possible on the very smooth surface of the tongue and cheek epithelium.
Question
Entamoeba histolytica

A)causes amebiasis.
B)may form cysts.
C)cysts survive passage through the stomach.
D)may produce a cytotoxic enzyme.
E)All of the choices are correct.
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Deck 24: Digestive System Infections
1
The chronic inflammatory process involving the gums and tissues around the teeth is called

A)dental caries.
B)periodontal disease.
C)dental plaque.
D)root caries.
B
2
The viral disease that characteristically infects the parotid glands is

A)measles.
B)herpes.
C)chickenpox.
D)mumps.
D
3
The diarrhea of cholera has been described as

A)a viscous fluid.
B)small in volume.
C)somewhat watery.
D)a rice water stool.
D
4
Where in the body does the latent, non-infectious, non-replicating form of the herpes simplex virus persist?

A)motor neurons
B)red blood cells
C)cranial nerves
D)sensory nerves
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
5
The most common infectious disease of humans is
A)

A)the common cold.
B)dental caries.
C)hepatitis
D)halitosis
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
6
This mineral, typically added to drinking water, makes enamel more resistant to dissolving in acid.

A)calcium
B)chlorine
C)chloramine
D)fluoride
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
7
The initial attachment required for establishment of an intestinal infection is by

A)flagella.
B)cilia.
C)pseudopodia.
D)pili.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
8
The principal cause of dental caries is

A)S.mutans.
B)S.salivarius.
C)S.mitis.
D)S.sanguis.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
9
Who determined that the cholera outbreak in 1850s London was due to contaminated water and approached the problem by removing the pump handle at the contaminated site?

A)Pasteur
B)Snow
C)Koch
D)Smith
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
10
H. pylori appears to have some connection with

A)acid reflux disease.
B)ulcers.
C)dental caries.
D)stomach cancer.
E)ulcers AND stomach cancer.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
11
The passage from the mouth to the anus is termed the

A)gut canal.
B)oral cavity.
C)grand canal.
D)alimentary canal.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
12
Cholera is the classic example of a(n)

A)food-borne illness.
B)zoonosis.
C)opportunist.
D)very severe form of diarrhea.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
13
A painful finger infection attributable to herpes virus is known as a(n)

A)finger sore.
B)abrasion lesion.
C)furuncle.
D)herpetic whitlow.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
14
Collections of bacteria that adhere to the surfaces of the teeth are called

A)dental caries.
B)dental plaque.
C)halitosis.
D)periodontal disease.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
15
Part of the ability of S. mutans to produce dental caries depends on its ability to

A)invade plaque and dissolve the gums.
B)convert sucrose to lactic acid.
C)convert proteins to sugars.
D)attach to the gums.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
16
Which of the following has shown some effectiveness in treating a herpes infection?

A)AZT
B)protease inhibitors
C)acyclovir
D)cephalosporin
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
17
The toxins involved in intestinal infections typically

A)kill cells by inhibiting protein synthesis.
B)modify cell physiology resulting in increased secretion of water and electrolytes.
C)modify cell physiology resulting in decreased secretion of water and electrolytes.
D)kill cells by inhibiting DNA synthesis.
E)kill cells by inhibiting protein synthesis AND modify cell physiology resulting in increased secretion of water and electrolytes.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
18
Mumps is a good candidate for elimination from the population due to

A)the existence of an effective vaccine.
B)a human only reservoir.
C)the absence of a latent state.
D)a single serotype.
E)All of the choices are correct.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
19
H. pylori is, in part, able to survive in the stomach by its ability to produce

A)lactic acid from sugar.
B)fatty acids from sebum.
C)neutralizing proteins from glucans.
D)ammonia from urea.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
20
The symptoms of cholera are due to the action of

A)an endotoxin.
B)modified mucus.
C)flagella.
D)an exotoxin.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
21
The food products most commonly contaminated with Salmonella strains are

A)meat and seafood.
B)milk and cheese.
C)fruit and vegetables.
D)eggs and poultry.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
22
Which of the following groups give rise to a disease similar to that caused by Shigella sp.?

A)enterotoxigenic
B)enteroinvasive
C)enteropathogenic
D)enterohemorrhagic
E)All of the choices are correct.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
23
Shigella

A)are themselves nonmotile.
B)may be pushed from cell to cell by actin tails.
C)utilize pili to move.
D)utilize flagella to move.
E)are themselves nonmotile AND may be pushed from cell to cell by actin tails.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
24
Viral gastroenteritis that affects people of all ages and usually lasts less than 3 days is caused by

A)herpes.
B)
B)hepatitis
C)norovirus.
D)rotavirus.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
25
V. cholera and most salmonellas are

A)killed by acid conditions.
B)stimulated by acid conditions.
C)killed by low concentrations of salt.
D)killed by neutral conditions.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
26
Which group produces a toxin somewhat similar to that produced by Shigella dysenteriae?

A)enterotoxigenic
B)enteroinvasive
C)enteropathogenic
D)enterohemorrhagic
E)All of the choices are correct.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
27
A mysterious sequel to

A)Reye's syndrome.
B)Tourette's syndrome.
C)Pasteur's syndrome.
C)jejuni infections is
D)Guillain-Barré syndrome.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
28
The most notorious typhoid carrier was

A)Typhoid Tilly.
B)Typhoid Tom.
C)Typhoid Mary.
D)Typhoid Mark.
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
29
In which of these organs does a carrier of typhoid bacilli maintain the bacteria?

A)liver
B)gallbladder
C)Peyer's patches
D)colon
E)liver AND Peyer's patches
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Unlock Deck
k this deck
30
The animal(s) often associated with Salmonella strains is/are

A)turtles.
B)iguanas.
C)baby chickens.
D)ducks.
E)All of the choices are correct.
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
31
Hepatitis A spreads via

A)the respiratory route.
B)blood transfusion.
C)body fluids.
D)the fecal-oral route.
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Unlock Deck
k this deck
32
Shigella and cholera toxin both

A)have an A-B arrangement.
B)work through ADP ribosylation.
C)increase cAMP levels.
D)prevent protein synthesis.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
33
Protozoan infections are typically spread by

A)the respiratory route.
B)blood transfusion.
C)body fluids.
D)the fecal-oral route.
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Unlock Deck
k this deck
34
HBV is mainly spread by

A)blood.
B)blood products.
C)semen.
D)saliva.
E)blood, blood products AND semen.
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
35
Viral gastroenteritis in infants and children is most commonly caused by

A)herpes.
B)
B)hepatitis
C)Norwalk virus.
D)rotavirus.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
36
A common source of cholera infection is

A)acid rain.
B)unpasteurized milk.
C)fecal contaminated material, especially water.
D)boiled water.
E)acid rain AND boiled water.
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
37
The primary treatment for cholera is

A)the administration of antibiotics.
B)vaccination.
C)by blood transfusion.
D)simply rehydration.
E)vaccination AND by blood transfusion.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
38
Most cases of Salmonella gastroenteritis have a(n)

A)water source.
B)human source.
C)plant source.
D)animal source.
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
39
The most common chronic blood-borne infection in the U.S. is

A)hepatitis A
B)hepatitis B
C)hepatitis C
D)hepatitis D
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
40
The most commonly identified waterborne illness in the United States is

A)amoebiasis.
B)cryptosporidiosis.
C)balantidiasis.
D)giardiasis.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
41
Cyclospora cayetanensis has, so far, not been identified with an animal source.
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Unlock Deck
k this deck
42
H. pylori appears connected to stomach cancer and ulcers.
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Unlock Deck
k this deck
43
The mumps virus initially infects the respiratory tract.
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Unlock Deck
k this deck
44
Sucrose is one of the major contributors to the development of dental caries.
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Unlock Deck
k this deck
45
Most North American outbreaks of Cyclospora cayetanensis have been associated with

A)cattle.
B)iguanas.
C)imported leafy vegetables and berries, especially raspberries.
D)chickens.
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
46
Cyclosporiosis is transmissable from person to person.
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k this deck
47
The infectious dose of cholera is much larger than that for Shigella.
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k this deck
48
C. parvum may infect

A)dogs.
B)pigs.
C)cattle.
D)humans.
E)All of the choices are correct.
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Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
49
The oocytes of Cyclospora cayetanensis

A)are mature when eliminated in the stool.
B)do not contain sporozoites when passed in the feces.
C)are smaller than the oocytes of Cryptosporidium parvum.
D)give rise to three sporozoites.
E)All of the choices are correct.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
50
Why might it be more difficult to prepare a vaccine against noroviruses than against rotaviruses?

A)We haven't been able to culture noroviruses in a lab setting yet.Without a starting culture, we can't create a vaccine.
B)Noroviruses are RNA viruses, where rotaviruses are DNA viruses.RNA viruses mutate far more easily than DNA viruses, so we COULD make a vaccine, but it would be rendered useless fairly quickly as the virus mutates.
C)We lack a proper culturing method for large-scale production of target cells for norovirus, whereas we have such a system for the target cells of rotaviruses.Without a system to get large numbers of target cells, we can't produce a vaccine.
D)Norovirus is much more infectious than rotavirus.As such, it's much harder to work with safety.This makes production of a vaccine too dangerous and unpredictable.
Unlock Deck
Unlock for access to all 60 flashcards in this deck.
Unlock Deck
k this deck
51
Why would you expect acyclovir to be ineffective against latent HSV infections?

A)This is an antibacterial drug, and HSV is a virus.
B)This is an antifungal drug, and HSV is a virus.
C)This drug directly inhibits DNA polymerase activity-cells that are latently infected with HSV have no DNA polymerase activity.
D)This drug is a nucleoside analogue-it becomes activated by a viral enzyme that is produced only when the virus is replicating.As such, if the virus is latent, the enzyme to activate the drug is not present (and the drug is ineffective).
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k this deck
52
Virulent strains of shigella typically carry a large plasmid.
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k this deck
53
Both Giardia and
C.parvum are resistant to chlorine.
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Unlock Deck
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54
Giardiasis may be contracted from

A)another person.
B)clear mountain streams.
C)chlorinated city water.
D)cold filtered beer.
E)another person, clear mountain streams AND chlorinated city water.
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55
Explain how Vibrio cholerae causes cholera without apparent damage to the intestinal epithelium.

A)This microbe causes destruction of the cellular structures underneath the intestinal epithelium-this is what induces the watery rice-stool characteristic of the illness.This leaves the overlying intestinal epithelium intact.
B)This microbe directly invades the intestinal epithelial cells, but does not kill them.Instead, while multiplying inside them, it causes them to secrete large amounts of chloride ions.This induces water to follow by osmosis, resulting in the watery rice-stool characteristic of the illness.
C)This microbe attaches to the surface of intestinal epithelial cells, secreting an exotoxin that causes the epithelium to secrete large amounts of chloride ions.This induces large amounts of water to follow by osmosis, resulting in the watery rice-stool characteristic of the illness.
D)The inflammatory reaction to the presence of this microbe causes the watery rice-stool characteristic of the illness.Therefore, it's technically the immune response that initiates the disease, although this response is induced by the presence of the microbe on the intestinal epithelium.
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56
The bacteria primarily responsible for dental caries is Streptococcus mutans.
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57
Would you expect an individual with giardiasis who has diarrhea to be more likely to transmit the disease than an individual with giardiasis who does NOT have diarrhea? Why or why not?

A)No-this illness is spread by respiratory droplets, so diarrhea as a symptom shouldn't matter for transmission of the disease.
B)No-this illness is spread by sexual contact, so diarrhea as a symptom shouldn't matter for transmission of the disease.
C)Yes-this illness is spread by the fecal-oral route, so presence of diarrhea as a symptom should dramatically increase the possibility of transmission of infection.
D)Yes-this illness is spread by insects that feed on contaminated fecal matter, becoming infected themselves.The disease is spread to new individuals when these infected insects bite a susceptible person, transmitting the cysts of the protozoan.As such, diarrhea as a symptom would increase the risk of transmission through biting insects to new individuals.
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58
The saliva of asymptomatic carriers of herpes simplex is commonly infectious.
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59
Why is it that the tongue and cheek epithelium doesn't provide a sufficient anaerobic environment for plaque anaerobes to grow, but the surface of teeth might?

A)The epithelium is supplied with oxygen by capillary beds.This makes it a relatively aerobic environment and hostile to anaerobes.
B)The tooth enamel is supplied with oxygen by capillary beds.This makes it a relatively anaerobic environment and hostile to aerobes.
C)The surface of the tongue and cheek are constantly scraped by the action of consuming food.Layers of bacterial growth that might help to supply an anaerobic environment are scraped away, exposing lower levels to oxygen-rich air.
D)The surface of teeth (especially the molars) have many pits and crevices that can serve as 'pockets' for layers of bacteria to grow in.Once the layers get deep enough, the bottom portions are anaerobic.This isn't possible on the very smooth surface of the tongue and cheek epithelium.
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60
Entamoeba histolytica

A)causes amebiasis.
B)may form cysts.
C)cysts survive passage through the stomach.
D)may produce a cytotoxic enzyme.
E)All of the choices are correct.
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