HEPATITIS VIRUSES – C, D, E

HEPATITIS VIRUSES – C, D, E

Definition:

• Hepatitis C virus (HCV): A single-stranded RNA virus belonging to the family Flaviviridae.
• Hepatitis D virus (HDV): A single-stranded RNA virus belonging to the family Hepadnaviridae.
• Hepatitis E virus (HEV): A single-stranded RNA virus belonging to the family Hepeviridae.

Causes:

• HCV: Transmitted through blood-to-blood contact (e.g., needle sharing, unsterile tattoo equipment) and from mother to child during birth.
• HDV: Requires co-infection with hepatitis B virus (HBV) for replication; transmitted through blood-to-blood contact and from mother to child during birth.
• HEV: Transmitted through fecal-oral contact with contaminated water or food.

Types:

• HCV: Genotypes 1-7, with genotype 1 being the most common.
• HDV: Two main genotypes, with genotype 1 being the most common.
• HEV: Four main genotypes, with genotype 1 being the most common.

Pathogenesis:

• HCV:
  1. Virus enters liver cells → viral RNA replication → production of viral proteins.
  2. Viral proteins cause liver cell damage and inflammation.
  3. Immune response is triggered, leading to chronic inflammation and liver damage.
  4. Chronic infection can lead to cirrhosis and hepatocellular carcinoma.
• HDV:
  1. Requires HBV for replication; HDV uses HBV surface antigen as its envelope protein.
  2. HDV causes liver cell damage and inflammation.
  3. Immune response is triggered, leading to chronic inflammation and liver damage.
  4. Co-infection with HDV and HBV increases the risk of liver disease.
• HEV:
  1. Virus enters liver cells → viral RNA replication → production of viral proteins.
  2. Viral proteins cause liver cell damage and inflammation.
  3. Immune response is triggered, leading to acute inflammation and liver damage.
  4. Chronic infection is rare.

Morphology:

• HCV: 50-60 nm in diameter, envelope protein, and single-stranded RNA genome.
• HDV: 36-43 nm in diameter, envelope protein, and single-stranded RNA genome.
• HEV: 32-34 nm in diameter, envelope protein, and single-stranded RNA genome.

Clinical Features:

• HCV:
  1. Acute infection: asymptomatic or mild symptoms (e.g., jaundice, fatigue).
  2. Chronic infection: asymptomatic or mild symptoms (e.g., fatigue, weight loss).
  3. Complications: cirrhosis, hepatocellular carcinoma, and liver failure.
• HDV:
  1. Acute infection: asymptomatic or mild symptoms (e.g., jaundice, fatigue).
  2. Chronic infection: chronic hepatitis, cirrhosis, and hepatocellular carcinoma.
  3. Co-infection with HDV and HBV increases the risk of liver disease.
• HEV:
  1. Acute infection: jaundice, fatigue, nausea, and abdominal pain.
  2. Chronic infection is rare.

Complications:

• HCV: cirrhosis, hepatocellular carcinoma, and liver failure.
• HDV: chronic hepatitis, cirrhosis, and hepatocellular carcinoma.
• HEV: acute liver failure and mortality.

Diagnosis:

• HCV: serological tests (e.g., ELISA, RIBA), molecular tests (e.g., PCR), and liver biopsy.
• HDV: serological tests (e.g., ELISA, RIBA), molecular tests (e.g., PCR), and liver biopsy.
• HEV: serological tests (e.g., ELISA), molecular tests (e.g., PCR), and liver biopsy.

Management:

• HCV: antiviral therapy (e.g., interferon, ribavirin), liver transplantation.
• HDV: antiviral therapy (e.g., interferon, ribavirin) combined with HBV treatment.
• HEV: supportive care (e.g., hydration, nutrition), antiviral therapy (e.g., ribavirin).

Memory Trick:

• HCV: "Hepatitis C Virus: Hurt Liver, Hurt Life"
• HDV: "Hepatitis D Virus: Danger of Co-Infection"
• HEV: "Hepatitis E Virus: Easy to Contract, Hard to Cure"

Note: The above memory tricks are for educational purposes only and may not be suitable for everyone.