Hepatitis

Any inflammatory liver disease can be acute or chronic. Depending on the course of the disease, the symptoms of hepatitis can be more pronounced or milder, but usually include jaundice, decreased appetite, weakness. Hepatitis is considered acute when the disease lasts less than 6 months, and chronic when it lasts longer. The most common causes of hepatitis in the human body are viruses, but the disease can also be caused by various substances that are toxic to the body (alcohol, certain drugs, organic solvents, etc.), other infections, or autoimmune processes. Several types of hepatitis caused by viruses are distinguished. Hepatitis A is caused by a single-stranded RNA picornavirus; the disease spreads through the oral-fecal route and airborne droplets. The viruses in the infected person’s stool infect the soil, water, food, household items, hands. Hepatitis A is an acute infection, with an incubation period of 2-6 weeks (average of 28 days). It most commonly affects children and young people, with outbreaks usually occurring in the autumn. The incidence increases periodically every 3-5 years. After recovery, immunity is formed for the rest of life. Maternal antibodies protect the fetus and later the newborn from the disease for about a year. Hepatitis B, also known as serum hepatitis (contracted parenterally), is caused by a highly virulent virus with double-stranded DNA. The source of this virus is patients with chronic hepatitis and asymptomatic carriers of the virus. The virus spreads through damaged skin, mucous membranes, during various procedures with inadequately sterile instruments, by transfusion of infected blood or its components. Additionally, the disease spreads sexually, and the mother can transmit it to the fetus. Hepatitis B is often associated with the development of cirrhosis and malignant tumors in the liver. Hepatitis C is caused by a single-stranded RNA virus. It is most commonly contracted through blood transfusion. The disease is chronic, often asymptomatic, but after many years, cirrhosis can develop as a consequence of the disease. There is no vaccine for this type of hepatitis. The virus causing Hepatitis D, Hepatitis delta virus, is a satellite of the hepatitis B virus, having a single-stranded circular RNA. Infection with this virus occurs simultaneously with hepatitis B virus and greatly complicates the course of the disease. Hepatitis E is caused by a single-stranded RNA virus; the routes of transmission are similar to hepatitis A. Hepatitis E is more common in developing countries with a hot climate.

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