Hepatitis B

Definition: Hepatitis B (HBV)

According to The American Heritage Dictionaries, Hepatitis B is "an infection of the liver that is caused by a DNA virus, which is transmitted by contaminated blood or blood derivatives in transfusions, by sexual contact with an infected person, or by the use of contaminated needles and instruments". Unlike hepatitis A, hepatitis B virus can cause both acute and chronic forms of the disease, and is one of the commonest chronic infectious diseases worldwide.

In acute hepatitis B the inflammation develops quickly and it last for a short period of time (usually a complete recover can appear in maximum several months). In almost six month, most people suffering of acute hepatitis B will fully recover and will develop antibodies that will provide them immunity for their entire life. The chronic hepatitis B appears when the liver fails to fully recover and it can evolve for many years without symptoms.

Statistics revealed that most adults (over 95%) with acute hepatitis B will recover completely, becoming immune to a future infection with hepatitis B virus. Unfortunately, that is not the case with children infected with hepatitis B virus. Most infants and children infected with acute hepatitis B virus will become chronically infected.

The risk of becoming chronically infected depends on the age at the time of infection. More than 90% of newborns, about 50% of children, and less than 5% of adults infected with hepatitis B develop chronic hepatitis.

Short history of Hepatitis B

Although hepatitis had been known for centuries, nobody really knew what caused it until the 1940s when doctors began to suspect that a virus carried in human blood was responsible for the that disease. The first step in discovering Hepatitis B Virus was took in 1963 when Dr. Baruch Blumberg and colleagues identified a protein (the "Australia antigen") that had an unusual reaction to antibodies from patients who had received blood transfusions. The association of this protein with infectious hepatitis was discovered 3 years later by several investigators, when the scientists begun to understand that for reducing the risk of infection with hepatitis B, they should test the blood for the virus before transfusions.

Hepatitis B incubation period and infectivity

The hepatitis B virus has an incubation period virus which ranges from 45 to 160 days (mean = 100 days). Usually symptoms develop within 30-180 days of exposure to the virus, but it should be said that half of people infected with hepatitis B virus don't present any sign on infection. The acute form of hepatitis B presents some symptoms, but that is not the case in the chronic infection with hepatitis B virus, which almost always doesn't induce any symptoms. Most people suffering of acute hepatitis B present flu-like symptoms accentuated by nausea, anorexia, malaise and fatigue, pain over the liver or jaundice. The symptoms of acute hepatitis last, on average, 1 to 3 months.

During this time, the person is extremely contagious. The virus isn't very resistant in the usual environment - it is believed that normal hot wash in a washing machine is capable to kill the virus from clothing, and also using some washing-up liquid and hot water will kill the virus from plates and cutlery.

Hepatitis B Hepatitis B Symptoms