Hepatitis C virus is a –
**Core Concept**
Hepatitis C virus (HCV) is a single-stranded RNA virus belonging to the Flaviviridae family. It primarily causes liver inflammation, leading to chronic liver disease, cirrhosis, and hepatocellular carcinoma. The virus is transmitted through blood-to-blood contact, often through shared needles or unsanitary medical equipment.
**Why the Correct Answer is Right**
HCV has a unique ability to evade the host's immune system, leading to chronic infection in most cases. The virus enters hepatocytes through the CD81 receptor, which is essential for its replication. The viral genome is then translated into a polyprotein, which is processed into individual proteins necessary for viral replication and assembly. The RNA-dependent RNA polymerase (RdRp) enzyme is crucial for HCV replication.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the question. The correct answer should describe the type of virus, not its characteristics or replication mechanisms.
**Option B:** This option is incorrect because HCV is not a DNA virus; it is a single-stranded RNA virus.
**Option C:** This option is incorrect because HCV is not a retrovirus; it does not require reverse transcription to replicate.
**Clinical Pearl / High-Yield Fact**
HCV is primarily transmitted through blood-to-blood contact, making needle sharing and unsanitary medical equipment significant risk factors for infection. Screening for HCV in high-risk populations, such as injection drug users, is essential for early detection and treatment.
**Correct Answer: B. RNA virus.**