Amebiasis FAQs

Amebiasis is an intestinal illness caused by a microscopic parasite called Entamoeba histolytica. The para produces cysts, which are passed from the body in the stool.

Symptoms appear 2-4 weeks after infection; however, sometimes, it may take a few days, several months or even years before becoming ill. Nine in ten people who carry E. histolytica in their feces have no symptoms, but can still pass the disease on to others. The symptoms are often mild and can include loose stools, stomach pain, and stomach cramping.

A severe form of amebiasis causes stomach pain, bloody stools, and fever. Liver abscesses and brain or lung infections occur infrequently. How common is amebiasis? Although anyone can have this disease, it is most common in people who live in developing countries that have poor sanitary conditions. In the United States, amebiasis is most often found in immigrants from developing countries. It also is found in people who have traveled to developing countries. In parts of Africa, Latin America, India, and Southeast Asia, amebiasis is endemic (generally or constantly found in persons living in a particular place). In the United States, up to 4% of the population probably carries the parasite.

Amebiasis can affect anyone, however, the disease mostly occurs in young to middle-aged adults. People who travel to areas of the world, which do not have a sanitary water supply, are at greater risk for getting amebiasis. Men who have sex with men can become infected and can get sick from the infection, but they often do not have symptoms.

The infection can spread when infected people do not dispose of their feces in a sanitary manner or do not wash their hands properly after using the toilet. Contaminated hands can then spread the parasites to food eaten by other people and surfaces that may be touched by other people. Hands can also become contaminated when changing the diapers of an infected infant. The disease may also spread sexually by oral-anal contact.

Follow good personal hygiene at all times and sanitation precautions when traveling in tropical countries where poor sanitation exists (see below). Avoid sexual practices that may lead to fecal-oral transmission. Safer sex measures, such as the use of condoms and dental dams for oral/anal contact, may help prevent infection.

Food handlers, childcare workers, and healthcare workers with amebiasis must not work until symptoms have stopped. Children must not attend childcare centers or school until symptoms have stopped. However, the risk of spreading infection is low if the infected person is treated with antibiotics and practices good personal hygiene. Wash hands thoroughly with soap and hot running water for at least ten seconds:  

• Before preparing food
• Before eating
• After using the toilet or changing diapers
• After smoking
• After using a tissue or handkerchief.

Food handlers should:

• Thoroughly wash hands before touching food
• Use a paper towel or an air dryer to dry hands. Cloth towels are not recommended as they get dirty quickly and can spread germs from one person to another
• Thoroughly wash and cook raw vegetables
• Reheat food to an internal temperature of at least 170 ° F.

Call your health care provider if persistent diarrhea occurs. To trace the cause of the illness, it may be necessary to recall what you ate and drank and where you traveled in the weeks before you became ill.

Diagnosis of amebiasis can be difficult because amebic colitis (inflammation of the colon) is often confused with a variety of inflammatory bowel diseases. Infection is diagnosed by examining a stool sample under a microscope to look for the parasite. Because amebiasis can be difficult to diagnose and because the number of ameba found in the stool changes from day to day, more than one stool sample might be needed from different days. A blood test is available, but recommended only when it is suspected that the parasite has invaded other parts of the body.

When visiting developing countries you should:

• Avoid eating uncooked foods, particularly vegetables and fruit that cannot be peeled before eating
• Drink only packaged drinks, boiled water, or chlorinated and filtered water
• Avoid drinks containing ice
• Do not eat or drink milk, cheese, or dairy products that may not have been pasteurized.