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31 Cards in this Set
- Front
- Back
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What viruses found in the gut are associated with gastroenteritis
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Rotaviruses
Caliciviruses -Noroviruses -Sapoviruses Enteric Adenoviruses types 40 and 41 Astroviruses Coronaviruses -Human Toroviruses |
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Describe the Rotavirus genome
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Rotaviruses have a double-stranded RNA genome with 11 segments
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What occurs between related Rotavirus species?
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Reassortment
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When does Rotavirus become infectious?
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Rotavirus becomes infectious following proteolytic cleavage of the outer capsid protein VP4 (a surface spike protein)
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The recently approved Rotavirus vaccine was pulled out of use pending further study because of a link to:
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Intussusception
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What virus is the prototype strain of a group of related, noncultivatable human Caliciviruses associated with epidemic gastroenteritis?
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Norwalk virus
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Describe the stability of Norwalk virus
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Very stable virus particle, heat resistant, cooking of shellfish does not entirely eliminate the risk of transmission, resistant to chlorine
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Which is more frequent with Norwalk virus, diarrhea or vomiting?
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Vomiting
Norwalk is also named the “winter vomiting disease” |
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How does Norwalk virus affect the small intestine?
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Broadening and blunting of the villi of the proximal small intestine with intact mucosa
Mononuclear cell infiltrate and cytoplasmic vacuolization |
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Why would examination of stool be useful in cases of Norwalk virus?
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The absence of fecal leukocytes is a useful tool to exclude infection by enteroinvasive bacterial pathogens (like Shigella).
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Which types of Enteric adenovirus are associated with gastroenteritis?
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Adenovirus types 40 and 41
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How common are cases of Adenovirus gastroenteritis?
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Possibly the second most common viral cause of gastroenteritis (7-15% of all endemic cases)
Similar disease to Rotaviruses |
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Why do micro people like Astroviruses?
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Astroviruses can be grown in tissue culture
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Which RNA viruses have a crown-like appearance?
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Coronaviruses (Human Toroviruses)
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What is the second most common disease in the US with peaks in the winter
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Viral gastroenteritis
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What are the general features of viral gastroenteritis
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Major cause of morbidity in children in US and mortality in 3rd World
Short incubation and short duration of disease Most causitive agents can not be grown in culture and there are no animal models Repeated infections due to large number of agents without cross-protection Spread is person-to-person, food/water, and nosocomial |
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What does reo stand for in Reovirus
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Respiratory, enteric, orphan
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What are the general characteristics of Rotavirus
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Non enveloped, icosahedral, double-shelled capsid
Segmented, dsRNA genome – reassortment occurs between related species Replication is fast – yields virus 10-12 hours after infection Maturation occurs by budding thru ER – acquires pseudoenvelope |
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What cells does rotavirus infect
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Enterocytes in the villi of the small intestine
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How does Rotavirus cause diarrhea
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Virus replication damages the intestinal transport system resulting in impaired sodium and glucose absorption and osmotic diarrhea
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Rotavirus diarrhea fatalities are fully preventable if what treatment is used
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Oral rehydration therapy
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What is the most common gastrointestinal infection in infants 6-24 months old
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Rotavirus
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How is Rotavirus transmitted
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Fecal-oral route
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Important local immune factors against Rotavirus include what
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IgA and interferon. Immunity to one serotype may not protect against infection with another serotype
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How is Rotavirus diagnosed
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Virus isolation from stool
Rise in antibody titer Rotavirus ELISA test or rote tests |
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What are the characteristics of Caliciviruses
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Non enveloped, isosahedral capsid – chalice like
Positive sense ssRNA genome with cytoplasmic replication |
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How is Norwalk virus transmitted
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Fecal-oral spread. Seafood bars and shellfish are quite common sources of transmission. Also contaminated water and swimming pools
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What virus is associated mainly with pediatric endemic cases of gastroenteritis
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Sapovirus, one of the Caliciviruses. Diarrhea may be more common than vomiting, in contrast to Noroviruses
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What type of virus are the enteric adenoviruses
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Naked DNA viruses, 75nm in diameter
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What type of virus are the Astroviruses
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Small RNA viruses; non-enveloped, positive sense
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Astroviruses are associated with what type of gastroenteritis
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Cases of endemic gastroenteritis, usually in young children and neonates. Outbreak pattern resembles rotavirus--responsible for 10% of cases of gastroenteritis disease similar to Rotavirus and Adenoviruses
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