(amebic dysentery) What is amebiasis? Amebiasis is an intestinal illness caused by a microscopic intestinal parasite called Entamoeba histolytic. Approximately three cases are reported each year in Montana, most of which are imported. Who gets amebiasis? Anyone can get amebiasis, but it is recognized more often in people arriving from tropical or subtropical areas, individuals in institutions for the developmentally disabled. Rates are highest where sanitation is poor and feces can be contacted. How is this parasite spread? Amebiasis is contracted by swallowing the cyst stage of the parasite in contaminated food or water. It can also be spread by person-to-person contact. What are the symptoms of amebiasis? People exposed to this parasite may experience mild or severe symptoms or no symptoms at all. Fortunately, most exposed people do not become seriously ill. The mild form of amebiasis includes nausea, loose stools, weight loss, abdominal tenderness and occasional fever. Rarely, the parasite will invade the body beyond the intestines and cause a more serious infection, such as a liver abscess. How soon after exposure do symptoms appear? The symptoms may appear from a few days to a few months after exposure but usually within two to four weeks. For how long can an infected person carry this parasite? Some people with amebiasis may carry the parasite for weeks to years, often without symptoms. Where are the parasites that cause amebiasis found? Infected people are the only sources of the parasite. Fecal material from infected people may contaminate water or food which may serve as a vehicle to infect others. How is it diagnosed? Examination of stools under a microscope is the most common way for a doctor to diagnose amebiasis. Sometimes several stool samples must be obtained because the number of amoeba changes from day to day. What is the treatment for amebiasis? Specific antibiotics can be prescribed by a doctor to treat amebiasis. Should an infected person be excluded from work or school? Generally, it is not necessary to exclude an infected person from work or school. Casual contact at work or school is unlikely to transmit the disease. Special precautions may be needed by food servers or children enrolled in day care settings. Consult your local health department for advice in such instances. What precautions should the infected person follow? The most important precautions are careful hand washing after each toilet visit and proper disposal of sewage. Food handlers and individuals providing direct care to hospital or institutionalized patients should be excluded from sensitive activities until the completion of chemotherapy. 3/98 |