What Causes Hepatitis B?
There is only one cause of
hepatitis B -- an infection with the
hepatitis B virus (also known as HBV). The hepatitis B virus is a DNA virus that belongs to the genus O
rthohepadnavirus of the
Hepadnaviridae family.
When a person is infected with the hepatitis B virus, it is able to enter liver cells from the blood and then use those cells to make more copies of the virus. As more and more of the hepatitis B virus is made in the liver cells, the liver cells can become damaged and may even die.
A person infected with the hepatitis B virus may develop:
- A sudden onset of fever
- Extreme tiredness
- Nausea
- Lack of appetite
- Abdominal pain (stomach pain)
- Yellowing of the skin or whites of the eyes (jaundice).
Yet, not everyone infected with the hepatitis B virus will develop symptoms. With hepatitis B, a person can also develop a long-term liver infection (known as chronic hepatitis B).
The hepatitis B virus is spread through infected bodily fluids.
Among these bodily fluids are infected blood and blood products. Exposure to infected blood or blood products can occur through working in a laboratory or a dialysis unit, through infected needles used for tattoos or body piercing, or through sharing drug needles. In a few cases, people have been infected with hepatitis B by sharing objects that may have a tiny amount of blood on them, such as a toothbrush, razor, or tools used for manicures.
Hepatitis B is also spread through contact with other infected bodily fluids, such as semen, vaginal fluids, or saliva. A person cannot get the virus from a kiss or other normal everyday activities, such as hugging or shaking hands.
(Click Hepatitis B Transmission for more information about activities that put a person at high risk of developing the condition.)
