Gastroenteritis viruses

Question 1

Rotavirus

Answer 1

Key:

• non-enevloped icosahedral, double capsid, segmented dsRNA
• fecal-oral ingestion -> primary replication in villus epithelium -> polarized budding -> lysis
• VP4 attachment to sialic acid/integrins
• replication inside subviral particles
• VP1 (RdRp) transcription (within double-layered particle)
• copious watery diarrhea
• *histo flattened eptihelial cells and denuded villi
• *breastfeeding protective
• tx: ORS
• vaccine: rotateq (bovine virus genes), rotarix (live human virus)

Extra:

• most common cause of fatal gastroenteritis in children
• low calcium uncoating
• polarized budding for spread from cell to cell
• spreads from southwest to northeast during the winter
• diagnose with ELISA & PCR

Question 2

Norovirus (Norwalk viruses)

Answer 2

Key:

• nonenveloped icosahedral, positive-ssRNA
• oral ingestion (virus shed in vomit–aerosol– and feces–fecal/oral)
• *cannot be recovered in cell culture, stable against elcohol, ether, etc.
• vomiting > diarrhea + negative bacterial stool culture
• rehydration
• *noro-adults, rota-babies

Extra:

• replicates in both upper and lower GI tract
• most impt nonbacterial foodborne gastroeneteritis in adults
• re-infection due to waning immunity and antigenic variation
• virus she up to 1 month after illness
• no rapid test for diagnosis