# DBT JRF 2020 — Question 3

Exam: DBT JRF 2020 · Section: B · Topic: Microbiology · Difficulty: Easy

## Question

Hepatitis B is caused by a

## Options

- **A.** protozoan infection
- **B.** viral infection
- **C.** fungal infection
- **D.** bacterial infection

## Answer

Option B

## Explanation

Hepatitis B is caused by Hepatitis B Virus (HBV), a partially double-stranded DNA virus belonging to the family Hepadnaviridae (genus Orthohepadnavirus). The HBV genome (~3.2 kb) is a relaxed circular, partially dsDNA that replicates via an RNA intermediate (pregenomic RNA) through reverse transcription — making HBV unique among animal DNA viruses. Transmission occurs via blood/blood products, sexual contact, and vertical (mother-to-child) transmission. The virus infects hepatocytes causing acute and chronic hepatitis, and chronic infection is a major risk factor for hepatocellular carcinoma (HCC). A highly effective recombinant protein subunit vaccine (HBsAg) is available.

Source: https://mypyqbuddy.com/questions/hepatitis-b-is-caused-by-a-6a05a8a02adafec47029321b