Hepatitis is an inflammation of the liver. The liver, in the right side of the abdomen, is an important organ that processes nutrients, metabolizes medicines, and helps clear toxins from the body.
Most cases of hepatitis are caused by a virus. The three most common hepatitis viruses are hepatitis A, hepatitis B, and hepatitis C. (Hepatitis viruses D and E are rare in the United States.)
Hepatitis that's not caused by a virus can happen from things such as:
a bacterial infection
liver injury caused by a toxin (poison)
liver damage caused by interruption of the organ's normal blood supply
liver damage caused by interruption of the flow of bile through the liver
abdominal trauma in the area of the liver
an attack on the liver by the body's own immune system (called autoimmune hepatitis)
a problem with the liver itself
What Is Hepatitis A?
Hepatitis A virus (HAV) is contagious, usually spreading to others through food, drink, or objects contaminated by feces (poop) containing HAV. The hepatitis A vaccine has helped to make the infection rare in the United States and other developed countries.
Although a hepatitis A infection can cause severe symptoms, unlike some other hepatitis viruses, it rarely leads to long-lasting liver damage. People who have recovered from a hepatitis A infection have immunity to the virus and won't get it again.
Hepatitis B is a more serious infection. It can lead to cirrhosis (permanent scarring) of the liver, liver failure, or liver cancer, causing severe illness and even death.
Hepatitis B virus (HBV) spreads from person to person through blood or other body fluids. In the United States, this most commonly happens through unprotected sex with someone who has the disease or from injecting drugs with shared needles that aren't sterilized. It also can be passed from an infected mother to her unborn baby.
Like hepatitis B, the hepatitis C virus (HCV) spreads from person to person through blood or other body fluids, and can lead to cirrhosis or liver cancer. The most common way people become infected is by sharing drug paraphernalia such as needles and straws. People also can get hepatitis C from unprotected sex with an infected partner. And it can be passed from an infected mother to her unborn baby.
Hepatitis C is the most serious type of hepatitis. It's now one of the most common reasons for liver transplants in adults. Scientists have been trying for decades to develop a hepatitis C vaccine, but none has been successful yet. Fortunately, medicines can now treat people with hepatitis C and cure them in most cases.