Which form of viral hepatitis is transmitted through contaminated water and improperly handled shellfish?

Correct answer: A. Hepatitis A

• A. CORRECT. HEPATITIS A is transmitted by the FECAL–ORAL route, classically through contaminated water, raw or undercooked SHELLFISH harvested from polluted water, and food handled by an infected person. It causes an acute, self-limiting illness and does NOT progress to a chronic carrier state or to cirrhosis. An effective vaccine exists.
• B. Hepatitis D is a defective virus that can only replicate in the presence of hepatitis B surface antigen — it is blood-borne and requires HBV co-infection.
• C. Hepatitis B is BLOOD-BORNE and transmitted percutaneously, sexually and perinatally. It is the hepatitis of greatest occupational concern to dental personnel, and vaccination is required for clinical staff.
• D. Hepatitis C is BLOOD-BORNE, chiefly through injection drug use and historically through transfusion. It has a high rate of chronic infection but is not waterborne.

Note: The transmission split: A and E are FECAL–ORAL (A = shellfish and travel; E = notably dangerous in pregnancy). B, C and D are BLOOD-BORNE. Vaccines exist for A and B; vaccinating against B also protects against D.