South Dakota Department of Health
Office of Disease Prevention - 605-773-3737 — (1-800-592-1861 in South Dakota only)
This material is provided for informational purposes only and is not a substitute
for medical care. We are not able to answer personal medical questions. Please see your
health care provider concerning appropriate care, treatment or other medical advice.
What is amebiasis?
Amebiasis is an intestinal illness caused by a microscopic ameba parasite called Entamoeba histolytica.
Who gets amebiasis?
Anyone can get amebiasis, but it is found more often in people arriving from underdeveloped tropical or subtropical areas, individuals in institutions for the developmentally disabled and homosexual males.
How is this parasite spread?
People get amebiasis by swallowing the cyst stage of the parasite in contaminated food or water. It can also be spread by person-to-person contact, or sexually through oral-anal contact.
What are the symptoms of amebiasis?
People infected with ameba may experience mild or severe symptoms or no symptoms at all. Fortunately, most infected people do not become seriously ill. The symptoms of amebiasis include nausea, loose stools, bloody or mucoid diarrhea, 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 a few days to a few months after exposure but usually within 2 to 4 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 that may serve as a vehicle to infect others.
How is amebiasis 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 anti-parasitic drugs 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 handlers, staff employed in day care settings, or health care workers. These persons should be excluded from duties until after treatment and the person is no longer clinically ill.
What precautions should the infected person follow?
The most important precautions are careful hand washing after each toilet visit and proper disposal of sewage. Refrain from oral-anal contact until effectively treated.
How can I protect myself from amebiasis?
The most important precautions are careful hand washing before eating or preparing food. Raw foods should be properly cleaned. Refrain from oral-anal sexual contact until effectively treated.