Hepatitis A, once known as "infectious hepatitis," is a highly contagious liver disease caused by the hepatitis A virus (HAV). Hepatitis A is responsible for more than one-half of all viral hepatitis cases worldwide. In 1997 alone, over 30,000 cases of hepatitis A in the were reported to the Centers for Disease Control and Prevention (CDC). However, because of underreporting and because many hepatitis A infections are without symptoms, the actual number of infections in this country is estimated to be closer to 140,000 per year. HAV infection occurs with equal frequency in pregnant women as in the general population.
The hepatitis A virus is more widespread in overpopulated areas with poor sanitation.
The hepatitis A virus is "shed" through the feces of infected individuals and is spread mostly through direct person-to-person contact and exposure to contaminated water and food supplies. Hepatitis A may also be transmitted through direct blood contamination (sharing needles with an infected person).
Unlike most other types of viral hepatitis, a chronic carrier state (in which the person carries and transmits the virus without having symptoms) of hepatitis A does not exist. Therefore, HAV usually does not pose a special risk to a pregnant woman or her baby. Maternal infection does not result in birth defects. Moreover, transmission of infection from mother to baby almost never occurs.
If you are diagnosed with hepatitis A, your doctor is required by law to notify the local public health authority. This helps to identify the source of the infection and to prevent further outbreaks of the disease.
People at highest risk for infection in the are those who engage in personal contact with an infected person. Others at risk include:
- those who travel to countries with high or intermediate rates of hepatitis A, especially Africa, Asia (except Japan), Eastern Europe, the Middle East, South and Central America, Mexico, and Greenland;
- those who have oral-anal sexual contact;
- those who use illegal drugs;
- those with chronic liver disease;
- those who work with hepatitis A in a laboratory setting;
- those with blood clotting disorders or who receive clotting factor concentrates;
- children in day-care centers and who live in communities with high rates of hepatitis A, especially in the Southwestern U.S., Oregon, Washington, and Alaska;
- food handlers;
- residents and staff of institutions that care for the chronically ill or disabled; and
- people with a weakened immune system due to cancer, HIV, chronic steroid medications, or organ transplantation.
However, more than one-half of all people who contract hepatitis A have no identifiable risk factors.
The symptoms of hepatitis A infection range from none to severe. For example, most children under six years of age who develop hepatitis A have no symptoms. Only 30% of this population experience symptoms, which are usually mild, do not include jaundice, and usually clear up on their own.
By contrast, symptoms in adults usually appear abruptly, approximately two to four weeks after exposure. (An infected person is most contagious just before and during the time that symptoms begin to appear.) The following symptoms are common:
- abdominal pain;
- nausea and vomiting;
- loss of appetite;
- darkened urine;
- jaundice (yellowing of the eyes and skin); and
- liver enlargement.
About 70% of adults with HAV develop jaundice. About 15% require hospitalization for severe nausea, vomiting, and dehydration. Although the majority of hepatitis A cases last only one to four weeks, some cases may take several months to resolve completely.
In the majority of patients, long-term consequences of infection do not exist. Once recovered, a person has antibodies to hepatitis A that provide life-long immunity to the disease. However, there have been rare cases of relapsing hepatitis A within months of initial infection. In addition, there are approximately 100 deaths per year in the U.S. from severe HAV infections that lead to liver failure.
The economic consequences of hepatitis A are substantial. The combined cost of medical expenses, lost wages, and productivity in the U.S. is approximately $2,500 per adult case of hepatitis A. The total economic impact in the U.S. is estimated at $200 million per year.