Viral Hepatitis B

Term

Hepatitis B is a viral liver infection marked by the pathogen’s tendency to remain in the liver, eventually leading to liver cirrhosis or hepatocellular carcinoma.

Early Symptoms

At the onset of the disease, patients report anorexia, vague abdominal discomfort, nausea, vomiting, sometimes joint pain, and rashes.

Development of Jaundice

As the disease progresses, jaundice appears and intensifies.

Severe Form

Fulminant hepatitis B represents the most severe form of the disease and often results in death.

Diagnostic Method

Doctors diagnose hepatitis B through serological tests that search for virus antigens (Ag) and antibodies (Ab):

Hepatitis B surface antigen (HBsAg) and antibodies against it (anti-HBs)
Hepatitis B core antigen (HBcAg) and antibodies (anti-HBc)
Hepatitis B e antigen (HBeAg) and antibodies (anti-HBe)

All these markers can be detected in the blood, except for HBcAg, which is present only in liver tissue.

The Causative Agent

The hepatitis B virus, from the Hepnaviridae family, causes this infection. It has a double-stranded DNA composed of a nucleocapsid core (HBcAg) surrounded by an outer lipoprotein layer containing the surface antigen (HBsAg). HBsAg is heterogeneous, with a common antigen called ‘a’ and subdeterminants (d, y, w, and r), forming 4 main variants: adw, ayw, adr, and ayr. The geographical distribution of different variants varies.

Genotypes and Resistance

There are 8 known HBV genotypes. HBV is resistant to drying but sensitive to disinfectants. It can survive on environmental objects for up to 1 week and dies within several minutes to several tens of minutes when heated, depending on the environment.

Prevalence and Endemic Areas

Hepatitis B is prevalent worldwide with mild seasonal fluctuations in endemic areas.

At-Risk Populations

High-risk groups for HBV infection include injecting drug users, individuals with multiple sexual partners, family members and sexual partners of HBV carriers, healthcare workers performing invasive procedures, laboratory staff working with blood, prisoners, travelers staying in endemic countries for an extended period, and infants born to HB-infected or HBV-carrying mothers.

Source of Infection

Individuals with asymptomatic or clinical acute and chronic forms of HBV infection serve as infection sources. A person with HBsAg can potentially spread the infection. As HBeAg levels decrease and anti-HBe appears, the risk of transmission reduces. Qualitative and quantitative determination of HBeAg or virus DNA confirms the infection’s activity.

Prevention

Universal infant immunization stands as the most crucial measure for preventing HBV infection. This strategy ensures sufficient population immunity and prevents the spread of the infection.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė