Which two viruses can be found in shellfish?

• A. Human norovirus and Hepatitis A virus
• B. Rotavirus and Norovirus
• C. Astrovirus and Hepatitis E
• D. Adenovirus and Poliovirus

Answer: (A)

Shellfish can act as filters that concentrate viruses from polluted water, so some viruses become well-known culprits in shellfish-related illness. The two viruses most commonly linked to shellfish are human norovirus and hepatitis A virus. Norovirus is very contagious and has a low infectious dose, so eating raw or undercooked shellfish like oysters can readily trigger outbreaks. Hepatitis A virus also enters shellfish when sewage-contaminated water reaches harvest areas, and ingestion of contaminated shellfish can lead to hepatitis A.

The other virus pairs aren’t as strongly associated with shellfish outbreaks: rotavirus is mainly a cause of pediatric diarrhea and isn’t typically linked to shellfish contamination; astrovirus and hepatitis E are less commonly implicated in shellfish-related illness; adenovirus and poliovirus are not the classic culprits in shellfish-transmitted outbreaks.