The liver is made up of millions of cells. Each of the cells works in concert to produce protein and other products that enable the body to function. Hepatitis literally means inflammation of the liver, in particular the liver cells. There are many causes of hepatitis including drugs, infections, antibodies and genetic disorders.

The most common viruses to cause viral hepatitis are lettered as A, B, C, D, E and G. All of these viruses cause acute (short term) hepatitis, while only a few viruses tend to result in chronic (long term) hepatitis. Acute hepatitis can result in immediate liver failure, chronic infection or complete recovery without any lasting effect. Chronic hepatitis is the result of acute hepatitis that persists in the person's body and can result in liver failure, cancer or remain completely symptomless.

The viruses named B, C, and D may lead to chronic hepatitis, in which the infection is prolonged, sometimes lifelong.

The Centers for Disease Control estimates that more than 17 million people in the United States will be infected with hepatitis B or hepatitis C in the course of their lifetime, with chronic infection estimated in 4 million people with hepatitis C.

Death from chronic liver disease ultimately occurs in 15 to 25 percent of those chronically infected with hepatitis B. Approximately 10,000 people infected with hepatitis C die each year, according to the National Center for Infectious Diseases.

Hepatitis C in recent years has become the leading indication for a liver transplant. Nearly 50 percent of liver transplants are done for chronic hepatitis C infection.

Symptoms of viral hepatitis include jaundice (yellowing of the skin and eyes), fatigue, abdominal pain, loss of appetite, nausea, diarrhea and vomiting. Some people do not have symptoms until the damage to the liver is advanced.

Hepatitis is a viral pandemic.

Centers for Disease Control projections suggest that deaths in the U.S. from hepatitis C may increase to 38,000 by 2010.

The number of new hepatitis C infections in the United states has declined from an average of 240,000 in the 1980s to about 40,000. This due in part to testing of all blood products since 1990. The number of new hepatitis B infections has declined from an average of 450,000 in the 1980s to about 80,000 in 1999. The successful development of the HBV vaccine has helped decrease the number of new HBV cases. In fact, all seventh graders within the United States must have documented proof of successful HBV vaccination.

While a hepatitis B vaccine can prevent hepatitis B disease and its serious consequences, there currently is no vaccine to prevent hepatitis C.

TRANSMISSION OF VIRAL HEPATITIS

Y Confirmed transmission; R rarely transmitted; S suspected transmission; U uncommon

Other viruses, yet to be discovered, may also cause hepatitis and are called non A-G hepatitis. Hepatitis can result from toxins, drugs as well as many other viruses and infections.

Toxins can lead to a deterioration of the liver cells and may be caused by chemicals, alcohol, drugs, or industrial compounds. Alcohol abuse is a common cause of toxic liver damage.