I now live in Mexico and would like to know if I should be vaccinated for hepatitis A or anything else. The old-timers here seem to be taking a pill every six months that reduces the chances of amebas. Is that a good idea? My husband and I have both had problems with amebas and one incident with salmonella.

Caren

In Mexico and other less-developed countries, various foodborne infections are more common than they are in the United States and the more-developed countries. Hepatitis A, for example, is widespread in most of Mexico. The hepatitis A virus is spread by contaminated water and food, especially shellfish. Like any form of hepatitis, hepatitis A causes fever, right-side abdominal pain and jaundice (yellowing of the skin and eyes) as the major symptoms. While hepatitis A does not cause chronic liver disease, it can in rare cases be serious and even fatal.

There are three methods for preventing this infection. The first involves sanitation techniques, which can be extremely difficult in certain areas. Another way to prevent hepatitis A, and the only method available in the past, is to receive immunoglobulins (disease-fighting antibodies). These antibodies can prevent hepatitis A infection for several months.

The newest prevention technique is a vaccine against hepatitis A that has proved very effective. Immunity begins four weeks after administration, so if travel is planned before immunity takes effect, then immunoglobulin should be taken as well. Since you are not likely to be immune to hepatitis A, you should be vaccinated. The U.S. Centers for Disease Control recommends that everyone traveling to or working in a high-risk country receive the vaccine. Other groups for whom the vaccine is recommended include those with chronic liver disease and blood-clotting disorders, and those at high risk because of their jobs, such as workers in labs where hepatitis A is studied.

Amebiasis is an infection with an ameba called Entamoeba histolytica. The infection is common in less-developed countries such as Mexico. The most common form of the disease is gastrointestinal, and it often causes bloody diarrhea. Another form causes liver abscesses. You can avoid amebiasis by drinking only bottled or boiled water and avoiding fresh vegetables and other foods that could be contaminated with the organism. There are no recommendations to take any medication to prevent this infection. If the above guidelines are used, the risk of infection is probably low enough that no other intervention is necessary.