What is it about ?
An amoeba is a microorganism made up of a single cell. It can live freely or as a parasite. Amebiasis is an infection with an amoeba.
Entamoeba histolytica is an amoeba which can infect humans. Contamination can be done in two ways:
- by direct contact with the stool of an infected person,
- by indirect contact with the stools of an infected person, usually by drinking water or eating food contaminated by the stool, for example by fertilization with contaminated manure or by a poor sewage system.
When a person takes in contaminated water or food, the ingested cysts develop into amoebae. Entamoeba histolytica can survive in the large intestine. It produces cysts which are eliminated with the stool. In turn, these stools containing cysts can infect other people.
The incubation period, that is to say the time between the consumption of cysts and the disease, is very variable: 1 week to 4 months.
Amoeba can cause diarrhea. They can damage the intestinal wall, causing blood in the stool (amoebic dysentery). They are able to penetrate the wall of the intestine, invade the envelope that surrounds the intestines (the peritoneum) and cause peritonitis. They can pass into the bloodstream and end up in the liver, where they are responsible for forming a abscess.
Amebiasis can lead to death, especially through the formation of a abscess in the liver, but also as a result of diarrhea (bloody). This usually happens in people who live in poor sanitary conditions and have limited access to care.
Where, in whom and how often does it occur?
E. histolytica is present all over the world, but especially in the tropics and subtropics where sanitary conditions are poorer. Immigrants or travelers from these regions are among the groups at risk.
Around the world, roughly 1 in 10 people would be infected. Every year, 40 to 50 million people are infected. Out of 1000 infected people,
- 100 people develop amoebic dysentery,
- the infection spreads to the liver in less than 10 people,
- 1 to 2 people die, usually from the development of an amoebic abscess.
How is the diagnosis made?
Amebiasis can be diagnosed from laboratory tests on stool or on a sample of tissue from the large intestine (biopsy).
It is not always easy to find amoeba in the stool. This is why, in some cases, it is asked to bring the stool on three different days. In the laboratory, the stool is examined with special markers capable of detecting amoebae.
What can you do ?
To avoid catching amebiasis, use plain water. Treat impure water with iodine tablets in a good filtration system, or heat it over 50 ° C for more than 5 minutes. The cysts will then be destroyed, allowing you to drink the water safely. Chlorine added to drinking water does not destroy cysts.
The classic advice for food also holds true here: “boil it, cook it, peel it or forget it”. When you go on vacation, find out how to disease prevention. A reliable source is the website of theInstitute of Tropical Medicine.
After a stay abroad, if you suffer from stomach aches, of diarrhea severe and / or bloody and fever, you must inform your doctor and tell him which country you went to.
If you have diarrhea, remember to drink enough water, possibly with oral rehydration solution (ORS). It is a saline solution supplied in sachet; it promotes water absorption. The ORS is available in pharmacies.
What can the doctor do?
Amebiasis can be treated with a parasite medication. The doctor will inform you about the expected effects and side effects.
In some severe cases, hospitalization is necessary. Additional fluid will be administered there, along with the appropriate medication. A ultrasound can detect the presence of cysts in the liver.
Since a recurrence is possible, the doctor will order a new stool test a few weeks after treatment.
Want to know more?
- Amoebic dysentery – IMT – Institute of Tropical Medicine
- Healthy travel – IMT – Institute of Tropical Medicine
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