Hepatitis B Virus (HBV) Infection and Transmission

Hepatitis B Virus (HBV)

• HBV is a dsDNA virus, enveloped, and has reverse transcriptase.
• It is transmitted through body fluids, contaminated equipment, and from mother to baby during birth.
• About 292 million people are infected worldwide.
• HBV is very infectious, with approximately 30% of needle sticks resulting in infection in non-immune individuals.
• Patients who become carriers may develop chronic active or persistent hepatitis.
• Chronic infection can cause liver cancer.

Diagnosis of Hepatitis B

• Detection of surface antigen in patient's serum (HBsAg).
• Detection of antibodies to hepatitis B surface antigen (anti-HBs).
• Liver biopsy to determine the extent of liver damage.

Interpretation of HBV Serology

• HBsAg positive, anti-HBs negative, and anti-HBc positive: chronic infection.
• HBsAg negative, anti-HBs positive (>10 IU), and anti-HBc negative: vaccine-induced immunity.
• HBsAg negative, anti-HBs positive (>10 IU), and anti-HBc positive: previous natural infection and seroconversion.
• HBsAg negative, anti-HBs positive (<10 IU), and anti-HBc negative: possible vaccine failure.

Hepatitis B (Serum Hepatitis)

• Clinical manifestations: 70% of cases are asymptomatic.
• Generalized symptoms occur after 1-3 month incubation period.
• Virus infects liver hepatic cells, causing liver damage and jaundice.
• Chronic infection can cause development of primary liver cancer.

Prevention and Control of Hepatitis B

• Widespread screening.
• Vaccination.
• Preventing contact with HBV-infected secretions.
• Passive prophylaxis within 7 days of exposure.
• Treatment with nucleoside analogs (tenofovir with entecavir) and IFNalpha.

Hepatitis C (Chronic Hepatitis)

• Hepatitis C is an ssRNA linear virus in the Flaviviridae family.
• Transmission occurs via contaminated needles, from mother to fetus, or through organ transplants.
• About 70 million people are chronically infected worldwide.
• 75% of cases are mild or asymptomatic.
• The incubation period is 2-20 weeks.
• 40-60% may develop chronic liver disease.
• 20% may develop cirrhosis.
• Hepatocellular cancer may develop as a long-term sequelae.

Diagnosis of Hepatitis C

• Screening: Antibody Test (EIA).
• Confirmation testing: PCR, recombinant immunoblot assay.

Treatment of Hepatitis C

• Nucleoside analogs: sofosbuvir and ribavirin (>95% cure).
• No vaccine is available.

Hepatitis D

• Hepatitis D is a rare infection due to an incomplete RNA virus that requires the presence of hepatitis B.
• Found mostly in intravenous drug users (IVDUs).

This quiz covers the basics of Hepatitis B Virus (HBV), its transmission, and effects on the human body. Learn about the virus, its infectiousness, and potential health risks.