Reviewed by Dr. Clement J. Cheng
Acute viral hepatitis is an inflammatory disease of the liver caused by at least two strains of hepatrophic virus. The most common hepatitis virus is hepatitis A, and at least 50 percent of Americans have had the infection at some time and, as a result, they carry antibodies and are immune to it. Hepatitis B and C can lead to chronic (or long lasting) liver disease, and in some cases, liver failure. The hepatitis D virus cannot by itself cause hepatitis, but infection can result in a severe form of acute hepatitis when a person also carries the hepatitis B virus. Hepatitis E is similar to hepatitis A; however, it is not common in the United States. This virus is especially dangerous for pregnant women.
Chronic hepatitis (also known as inflammation of the liver) can follow infection by the hepatitis B, C, and D viruses. It can also occur as an autoimmune disease. Chronic hepatitis can be very serious, leading to cirrhosis. It can also lead to liver cancer in some cases. Chronic hepatitis C is almost as common as alcoholism in causing cirrhosis of the liver. Chronic hepatitis B accounts for almost 10 percent of all cases of liver disease and cirrhosis.
Autoimmune hepatitis is an autoimmune disease in which the immune system mistakenly attacks its own liver cells. It is primarily a disease of young women, but it can affect men and people of all ages.
Hepatitis A is more common in areas with poor standards of sanitation and hygiene. The infectious period is brief, usually lasting six days to six weeks, and during this time, the virus can spread. Transmission usually occurs through the ingestion of food or water that has been contaminated by fecal matter. Eating improperly cooked shellfish can also result in the virus’ spread. Recovery usually takes one to two months. In rare cases, it can lead to acute liver failure.
Hepatitis B transmits through infected blood (usually through blood transfusions and needles shared by intravenous blood users), sexual contact with infected semen, and possibly, through saliva. If a mother is infected, her baby can acquire the infection at birth. People who work in institutions, such as hospitals, also are vulnerable. The incubation period ranges from four to 12 weeks. Some people never develop hepatitis even if they become infected; others develop mild to severe cases. Hepatitis B can cause acute liver failure. The liver usually takes one to four months to recover from the initial attack. Some people become carriers; some develop chronic hepatitis; still, others develop cirrhosis and chronic liver failure.
Hepatitis C spreads in much the same way as hepatitis B; however, there is controversy over how easily the virus spreads through sexual contact. Many people infected with the hepatitis C virus do not develop acute hepatitis. On the average, the incubation period is seven weeks, but symptoms may go unnoticed for as long as 30 years. Some people develop severe hepatitis but do not suffer from acute liver failure. People with the acute form of the illness usually recover in three to four months. More than 50 percent of people with the hepatitis C virus develop chronic hepatitis. Some people will also develop cirrhosis, chronic liver failure, and/or liver cancer. Worldwide, the virus infects approximately 70 million people. An estimated 3.9 million Americans have chronic hepatitis. Those people with immune deficiencies, such as those people who have had organ transplants and those with acquired immunodeficiency syndrome (AIDS), have a higher risk of infection. Hepatitis D transmits through close personal contact rather than exposure to blood.
Hepatitis E transmits in much the same way as hepatitis A, primarily through the ingestion of contaminated food or water.
There is an incubation period between the time you become infected with a hepatitis virus and the time you exhibit symptoms. The incubation period varies depending on the virus. Some people with hepatitis B or C display no symptoms or very mild symptoms of acute hepatitis at first, but then, years later develop symptoms of chronic hepatitis.
