Amebiasis is an infection of the intestines caused by the parasite Entamoeba histolytica.
Amebic dysentery; Intestinal amebiasis
Causes, incidence, and risk factors
Entamoeba histolytica can live in the large intestine (colon) without causing damage to the instestins. However, sometimes, it invades the colon wall, causing
This condition occurs worldwide, but it is most common in tropical areas with crowded living conditions and poor sanitation. Africa, Mexico, parts of South America, and India have significant health problems associated with this disease.
Entamoeba histolytica is spread through food or water contaminated with stools. This contamination is common when human waste is used as fertilizer. It can also be spread from person to person — particularly by contact with the mouth or rectal area of an infected person.
Risk factors for severe amebiasis include:
Older or younger age
Recent travel to a tropical region
Use of corticosteroid medication to suppress the immune system
In the United States, amebiasis is most common among those who live in institutions or people who have returned from travel to an area where amebiasis is common.
Most people with this infection do not have symptoms. If symptoms occur, they are seen 7 to 28 days after being exposed to the parasite.
- Abdominal cramps
- Passage of 3 – 8 semiformed stools per day
- Passage of soft stools with mucus and occasional blood
- Excessive gas
- Rectal pain while having a bowel movement (
tenesmus) Unintentional weight loss
- Abdominal tenderness
- Passage of liquid stools with streaks of blood
- Passage of 10 – 20 stools per day
Signs and tests
Examination of the abdomen may show
Blood test for amebiasis
Examination of the inside of the lower large bowel (
Microscope examination of stool samples, usually over several days
Treatment depends on the severity of infection. Usually, metronidazole is given by mouth for 10 days. This is followed by paromomycin or diloxanide.
If you are vomiting, you may need to medications through a vein (
After treatment, the stool should be rechecked to make sure that the infection has been cleared.
The outcome is usually good with treatment. Usually, the illness lasts about 2 weeks, but it can come back if treatment is not given.
- Medication side effects, including nausea
- Spread of the parasite through the blood to the liver, lungs, brain, or other organs
Calling your health care provider
Call your health care provider if you have persistent diarrhea.
When traveling in tropical countries where poor sanitation exists, drink purified or boiled water and do not eat uncooked vegetables or unpeeled fruit. Public health measures include water purification, water chlorination, and sewage treatment programs.