Amebiasis is an infection caused by the parasite Entamoeba histolytica. People usually become infected by eating food or drinking water that has been contaminated.
In many cases, amebiasis, also called amebic colitis or intestinal amebiasis, does not cause symptoms. When the immune system is weaker or the parasite load is high, it can cause gastrointestinal symptoms such as diarrhea, belly pain, and general malaise.
Although amebiasis is usually easy to treat, it should be identified and treated as soon as symptoms appear. Early treatment helps prevent the infection from progressing and affecting organs such as the liver or lungs.
Main symptoms
The main symptoms of amebiasis are:
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Diarrhea
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Blood or mucus in the stool
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Abdominal pain
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Cramping
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Excessive tiredness
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General malaise
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Increased gas
According to the CDC, most people infected with Entamoeba histolytica do not get sick, but when illness occurs it often causes symptoms such as diarrhea and stomach pain.
Symptoms of amebiasis usually appear when there are many parasites in the intestine and/or the immune system is weakened. They typically start about 2 to 5 weeks after eating or drinking something contaminated with the parasite, so it is important to see a doctor if they occur.
In more severe cases, especially when the infection is not identified and treated, the parasite can pass through the intestinal wall and reach the liver, which can lead to abscess formation. It can also affect the diaphragm and lead to pleuropulmonary amebiasis.
In these cases, other symptoms may also occur, such as fever, chills, excessive sweating, nausea, vomiting, and alternating episodes of diarrhea and constipation.
Transmission and spread
Amebiasis spreads when people consume food or water contaminated with the parasite Entamoeba histolytica.
According to the World Health Organization (WHO), transmission is strongly linked to unsafe drinking water, inadequate sanitation, and poor hygiene, which is why the infection is more common in areas where food and water may be contaminated with feces.
Confirming a diagnosis
The initial diagnosis of amebiasis is made by a primary care provider or gastroenterologist based on a person’s signs and symptoms. A stool parasite test is also usually recommended to check for Entamoeba histolytica cysts in the stool.
If there is concern that other parts of the body may be affected, the doctor may also order an ultrasound or CT scan. Microbiological testing may also be requested if abscesses are present.
Treatment options
Treatment for amebiasis is decided by a healthcare provider based on the type and severity of the infection. Depending on the situation, they may prescribe metronidazole, paromomycin, iodoquinol, or tinidazole.
For extraintestinal amebiasis, a provider may recommend combined use of metronidazole and tinidazole.
It is also important to stay hydrated during treatment, since diarrhea and vomiting can cause significant fluid loss.