Which of the following sources is most likely to transmit hepatitis A?

Hepatitis A is primarily transmitted through the fecal-oral route, and one of the most common sources of infection is through contaminated food and water. Shellfish, particularly oysters and clams, can accumulate viruses when they are harvested from contaminated waters. If these shellfish are consumed raw or minimally cooked, they can transmit hepatitis A to the person eating them.

This makes shellfish from a contaminated water source a significant risk factor for hepatitis A transmission, as the shellfish do not have to exhibit visible signs of contamination for the virus to be present. Proper cooking of shellfish typically kills the virus, but when consumed raw, the risk remains high.

In contrast, while undercooked animal protein might pose a risk for other foodborne illnesses, it is not a common transmission route for hepatitis A. A cook with an infected hand sore could theoretically transmit the virus, but this option involves human error rather than contamination that arises during standard food preparation. A cross-contaminated cutting board may carry various pathogens, but hepatitis A is particularly associated with fecally contaminated water or food rather than surface contamination in typical food handling.