Hepatitis-B is an infectious disease caused by HBV ( hepatitis-B virus ) which affects liver and can cause acute and chronic infections. It was first discovered by Dr. Baruch Blumberg in the year 1965. It has a infectious lipid envelop containing surface antigen called as HBsAg. It also have an inner nucleocapsid composed of HBcAg with virally encoded polymerase.
Hepatitis-B virus(HBV) replicates through an RNA intermediate, produces and releases antigenic decay particles. HBsAg glycoproteins helps for the attachment of hepatitis-B virus to hepatocytes.Virus binds to polymerised human serum and serum proteins. Replication occurs when the virus penetrates the hepatocyte and releases its genetic material. The significance of integrated DNA in the replication of virus is still unknown, but these integrated DNA is found in hepatocellular carcinoma. The virion then releases from the hepatocyte without cell lysis.
Major Determinants of HBV Infection
- HBV infects the liver but doesn’t cause direct cytopathology. Cell mediated immune lysis of infected cells produces the symptoms and resolves the infection
- Insufficient immunity can lead to chronic disease. Chronic HBV disease predispose a person to more serious outcomes.
- Acute HBV infection have a resolution and symptoms include Jaundice and release of enzymes.
- Chronic HBV infection have mild symptoms and also causes Primary Hepatocellular Carcinoma and Liver Cirrhosis.
- Rapid onset of sickness with vomiting
- Yellowish skin and eyes
- Dark urine
- Abdominal pain
- Often these symptoms lasts a few weeks and rarely to death
- It may take 30-180 days for symptoms to begin
- The diagnostic procedures involve blood test, liver ultrasound which can show the amount of liver damage, liver biopsy.
- Generally, kit method also developed which gives the result in twenty minutes.
- This hepatitis-B virus is transmitted by exposure to infectious blood or body fluids infection. It even could spread through intravenous drug usage and sexual intercourse, other risk factors include working in healthcare, blood transfusions, dialysis etc. Tattoos and acupuncture let to a significant rise in number of cases in 1980’s.
- Babies born to chronic hepatitis-B virus positive mother are at higher risk for infection.
- HBV virus cannot be spread by holding hands, sharing eating utensils, kissing, hugging, coughing, sneezing or breast feeding.
- Transmission also occurs through needle sharing, ear piercing and through very close personal contact involving the exchange of semen, saliva and vaginal secretions (sex, childbirth etc).
- 15% population effected with the virus are infected during birth or childhood because infants and young children have an immature cell mediated immune response and are less able to resolve the infection. But they suffer less tissue damage and milder symptoms.
- Tenofovir disoproxil
- Tentovir alafenamide
- Interferon alpha etc.
- Vaccination is recommended by WHO in the first day of life.
Treatment, Prevention And Control
- FDA [Food and Drug Administration act] approved a more sophisticated plasma derived hepatitis-B vaccine for humans.
- This is a inactivated vaccine prepared from HBV infected donors. Currently recombinant HBV vaccines were approved.
- Transmission of hepatitis-B virus in blood or through blood has been greatly reduced by screening donated blood.
- Additional efforts to prevent transmission is avoiding lifestyles that facilitate the spread of disease.
- Vaccination is recommended for infants, children and people in high risk condition.
- HBV contaminated materials can be disinfected with 10% bleach solutions and are not generally activated by detergents.
- HBV can easily spread through blood transfusions, very close personal contact and from mothers to babies (if the mother is HBV positive). It cannot spread through holding hands, kissing, hugging and breast feeding.
- The symptoms are generally seen from 30-180 days and lasts for few weeks, rarely they can lead to death.
- Household contacts and sexual partners of HBV carriers are having as increased risk as the patients of haemodialysis.
- The vaccine is prepared from HBV infected donors, but now-a-days recombinant HBV vaccines are approved.
- Universal blood and body fluid precautions (screening the blood) are used to limit exposure to HBV.