Which hepatitis virus is a DNA virus?
**Core Concept**
The hepatitis viruses are a group of pathogens that cause liver inflammation and infection. They can be classified into two main types: DNA viruses and RNA viruses. This question requires the student to identify the hepatitis virus that belongs to the DNA virus category.
**Why the Correct Answer is Right**
The correct answer is Hepatitis B virus (HBV). HBV is a DNA virus that replicates by reverse transcription of its partially double-stranded DNA genome. This unique replication mechanism allows HBV to integrate into the host genome, leading to chronic infection and potentially hepatocellular carcinoma. The HBV genome encodes for several proteins, including the surface antigen (HBsAg) and the core antigen (HBcAg), which are essential for viral replication and pathogenesis.
**Why Each Wrong Option is Incorrect**
**Option A:** Hepatitis A virus (HAV) is an RNA virus that belongs to the Picornaviridae family. It is primarily transmitted through the fecal-oral route and causes acute hepatitis.
**Option B:** Hepatitis C virus (HCV) is an RNA virus that belongs to the Flaviviridae family. It is also primarily transmitted through blood-to-blood contact and causes chronic hepatitis.
**Option C:** Hepatitis D virus (HDV) is a defective RNA virus that requires the presence of HBV for replication. It is also transmitted through blood-to-blood contact and causes severe liver disease in co-infected individuals.
**Clinical Pearl / High-Yield Fact**
HBV is the only hepatitis virus that can be transmitted vertically from mother to child during childbirth. This mode of transmission highlights the importance of screening pregnant women for HBV and providing prophylactic measures to prevent vertical transmission.
**Correct Answer:** C. Hepatitis B virus (HBV)