Hepatitis B

Classification

Realm: Riboviria
Order: Blubervirales
Family: Hepadnaviridae
Genus: Orthohepadnavirus
Species: Hepatitis B virus

Structure

Genome: Partially double-stranded DNA (dsDNA-RT)
Capsid Shape: Icosahedral
Envelope: Enveloped
Size: ~42 nm in diameter
Special Features: Uses reverse transcription, integrates into the host genome in chronic infections

Transmission & Epidemiology

Natural Habitat: Humans
Geographic Distribution: Worldwide
Human Association: Pathogenic
Transmission: Bloodborne, sexual contact, perinatal (mother-to-child), sharing needles

Hepatitis B virus (HBV) is a highly infectious virus that primarily targets the liver, leading to acute and chronic hepatitis.

Virulence Factors: Surface antigens (HBsAg), HBx protein (interferes with tumor suppressors), immune evasion through chronic infection
Associated Diseases: Acute and chronic hepatitis, cirrhosis, hepatocellular carcinoma (liver cancer)
Clinical Symptoms: Jaundice, fatigue, abdominal pain, dark urine, nausea, liver inflammation
High-Risk Groups: Infants born to infected mothers, people who inject drugs, healthcare workers, individuals with multiple sexual partners

Chronic HBV infection is a leading cause of liver-related morbidity and mortality, with millions of people worldwide requiring lifelong monitoring and treatment.

The diagnosis of Hepatitis B virus (HBV) infection involves serological testing and molecular diagnostics to assess viral load and liver function.

Diagnostic Methods

HBsAg (Hepatitis B Surface Antigen) Test: Detects active HBV infection
Anti-HBc (Hepatitis B Core Antibody) Test: Identifies past or ongoing infection
HBeAg (Hepatitis B e Antigen) Test: Indicates active viral replication and high infectivity
HBV DNA Test:: Measures viral load to assess disease progression
Liver Function Tests (ALT, AST): Evaluates liver inflammation and damage
Liver Biopsy/Transient Elastography: Determines the extent of fibrosis or cirrhosis

Treatment Approaches

Antiviral Therapy: Nucleos(t)ide analogs (e.g., tenofovir, entecavir) to suppress viral replication
Interferon Therapy: Pegylated interferon-alpha to enhance immune response against HBV
Liver Transplantation: Considered for end-stage liver disease due to chronic HBV infection
Supportive Care: Regular monitoring, liver-protective measures (e.g., avoiding alcohol, hepatotoxic drugs)

Prevention Strategies

Universal hepatitis B vaccination, particularly for newborns and high-risk groups
Screening of blood and organ donors to prevent transmission
Safe injection practices and harm reduction programs for people who inject drugs
Education on HBV transmission, risk factors, and liver disease prevention

Preventing Hepatitis B infection requires a combination of vaccination, safe healthcare practices, and public health awareness efforts.

Global Impact

Hepatitis B is a major global health concern, affecting over 250 million people worldwide and contributing to significant liver-related morbidity and mortality.

~820K

Approximately 820,000 deaths occur annually due to HBV-related complications, including cirrhosis and liver cancer.

Despite the availability of an effective vaccine, HBV remains a significant global challenge, particularly in regions with inadequate healthcare infrastructure and limited vaccination coverage.