Viral hepatitis is liver inflammation caused by infection with a
virus.
The following viruses cause most cases of viral hepatitis:
- Hepatitis A virus (HAV)
- Hepatitis B
virus (HBV)
- Hepatitis C virus (HCV)
- Hepatitis D virus
(HDV)
- Hepatitis E virus (HEV)
A virus that causes hepatitis can be spread from one person to
another. Hepatitis B, C, and D viruses are spread when a person comes in
contact with blood, semen, or vaginal fluid (including menstrual blood) that is
infected with one of these viruses. Hepatitis A and E viruses are spread by
contaminated food and water or by coming in direct contact with contaminated
stool (feces). Hepatitis E is very rare in the United States. Hepatitis D only
occurs along with hepatitis B.
In their early (acute) stages, these viruses are difficult to tell
apart. However, several weeks to months after infection occurs, blood tests can
show which of the viruses is the cause of hepatitis (with the exception of
hepatitis E, for which a blood test is not widely available in the United
States).
The following viruses are less common causes of hepatitis and can be
diagnosed using blood tests: