Hepatitis D infection occurs only in conjunction with infection by which virus?

Hepatitis D infection occurs only in conjunction with infection by which virus?

• A. Hepatitis B
• B. Hepatitis A
• C. Hepatitis C
• D. Hepatitis E

Answer: (A)

Hepatitis D is a defective, satellite virus that cannot complete its life cycle without a helper virus. It relies on the Hepatitis B surface antigen (HBsAg) provided by Hepatitis B to coat its virions and enable replication. Because of this dependence, Hepatitis D infection can occur only in people who are infected with Hepatitis B— either at the same time or as a superinfection in someone with chronic Hepatitis B. In contrast, Hepatitis A, C, and E do not supply the necessary HBV envelope, so they cannot enable HDV infection. This is also why vaccination against Hepatitis B effectively prevents Hepatitis D.

Hepatitis D is a defective, satellite virus that cannot complete its life cycle without a helper virus. It relies on the Hepatitis B surface antigen (HBsAg) provided by Hepatitis B to coat its virions and enable replication. Because of this dependence, Hepatitis D infection can occur only in people who are infected with Hepatitis B— either at the same time or as a superinfection in someone with chronic Hepatitis B. In contrast, Hepatitis A, C, and E do not supply the necessary HBV envelope, so they cannot enable HDV infection. This is also why vaccination against Hepatitis B effectively prevents Hepatitis D.