Hepatitis B virus (HBV) is a member of the Hepadnaviridae family and is the primary cause of hepatitis B infection in humans. It is a small, enveloped DNA virus that specifically targets liver cells, leading to inflammation and damage to the liver. HBV is highly contagious and can be transmitted through various modes, including contact with infected blood or body fluids, sexual contact, and from mother to child during childbirth.
The virus is composed of an outer envelope containing viral surface antigens, and an inner core consisting of viral DNA and polymerase enzymes. Once the virus enters the body, it attaches to specific receptors on liver cells and enters them, where it releases its genetic material into the host cell. The viral DNA then undergoes replication and transcription, leading to the production of viral proteins and viral DNA copies.
HBV infection can lead to acute or chronic hepatitis, with chronic infection being the most common outcome. Chronic hepatitis B can result in long-term liver damage, including cirrhosis, liver failure, and hepatocellular carcinoma. Symptoms of hepatitis B infection include fatigue, jaundice, abdominal pain, dark urine, and loss of appetite.
Prevention of HBV infection primarily involves vaccination, as there is an effective and safe vaccine available. Treatment for chronic hepatitis B includes antiviral medications to suppress viral replication and reduce liver inflammation. Early diagnosis and appropriate medical management are crucial to prevent severe complications and to control the spread of the virus.
