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31 Cards in this Set

  • Front
  • Back
What viruses found in the gut are associated with gastroenteritis
Enteric Adenoviruses types 40 and 41
-Human Toroviruses
Describe the Rotavirus genome
Rotaviruses have a double-stranded RNA genome with 11 segments
What occurs between related Rotavirus species?
When does Rotavirus become infectious?
Rotavirus becomes infectious following proteolytic cleavage of the outer capsid protein VP4 (a surface spike protein)
The recently approved Rotavirus vaccine was pulled out of use pending further study because of a link to:
What virus is the prototype strain of a group of related, noncultivatable human Caliciviruses associated with epidemic gastroenteritis?
Norwalk virus
Describe the stability of Norwalk virus
Very stable virus particle, heat resistant, cooking of shellfish does not entirely eliminate the risk of transmission, resistant to chlorine
Which is more frequent with Norwalk virus, diarrhea or vomiting?
Norwalk is also named the “winter vomiting disease”
How does Norwalk virus affect the small intestine?
Broadening and blunting of the villi of the proximal small intestine with intact mucosa
Mononuclear cell infiltrate and cytoplasmic vacuolization
Why would examination of stool be useful in cases of Norwalk virus?
The absence of fecal leukocytes is a useful tool to exclude infection by enteroinvasive bacterial pathogens (like Shigella).
Which types of Enteric adenovirus are associated with gastroenteritis?
Adenovirus types 40 and 41
How common are cases of Adenovirus gastroenteritis?
Possibly the second most common viral cause of gastroenteritis (7-15% of all endemic cases)
Similar disease to Rotaviruses
Why do micro people like Astroviruses?
Astroviruses can be grown in tissue culture
Which RNA viruses have a crown-like appearance?
Coronaviruses (Human Toroviruses)
What is the second most common disease in the US with peaks in the winter
Viral gastroenteritis
What are the general features of viral gastroenteritis
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
What does reo stand for in Reovirus
Respiratory, enteric, orphan
What are the general characteristics of Rotavirus
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
What cells does rotavirus infect
Enterocytes in the villi of the small intestine
How does Rotavirus cause diarrhea
Virus replication damages the intestinal transport system resulting in impaired sodium and glucose absorption and osmotic diarrhea
Rotavirus diarrhea fatalities are fully preventable if what treatment is used
Oral rehydration therapy
What is the most common gastrointestinal infection in infants 6-24 months old
How is Rotavirus transmitted
Fecal-oral route
Important local immune factors against Rotavirus include what
IgA and interferon. Immunity to one serotype may not protect against infection with another serotype
How is Rotavirus diagnosed
Virus isolation from stool
Rise in antibody titer
Rotavirus ELISA test or rote tests
What are the characteristics of Caliciviruses
Non enveloped, isosahedral capsid – chalice like
Positive sense ssRNA genome with cytoplasmic replication
How is Norwalk virus transmitted
Fecal-oral spread. Seafood bars and shellfish are quite common sources of transmission. Also contaminated water and swimming pools
What virus is associated mainly with pediatric endemic cases of gastroenteritis
Sapovirus, one of the Caliciviruses. Diarrhea may be more common than vomiting, in contrast to Noroviruses
What type of virus are the enteric adenoviruses
Naked DNA viruses, 75nm in diameter
What type of virus are the Astroviruses
Small RNA viruses; non-enveloped, positive sense
Astroviruses are associated with what type of gastroenteritis
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