What is amebiasis?

Amebiasis is an intestinal illness caused by a microscopic parasite called Entamoeba histolytica.

Who gets amebiasis?

Anyone can get amebiasis, but it occurs more often in people arriving from tropical countries that have poor sanitary conditions, in individuals in institutions for the developmentally disabled, and in men who have sex with men.

How is amebiasis spread?

The disease can be spread through food or water that has been contaminated with feces (stool) from an infected person. It can also be spread from person-to-person through sexual practices with fecal-oral contact. Infected people are the only sources of the parasite.

What are the symptoms of amebiasis?

People exposed to this parasite might experience mild or severe symptoms or no symptoms at all. Only about 10% to 20% of people who are infected become sick, and most infected people do not become seriously ill. The symptoms of amebiasis include diarrhea, stomach pain, and stomach cramping. Amebic dysentery is a severe form of the disease that causes stomach pain, bloody stools, and fever. The parasite can spread outside of the intestine to other parts of the body, such as the lungs or brain, but this is very uncommon.

How soon after exposure do symptoms appear?

The symptoms can appear a few days to a few months or years after exposure, but usually occur within two to four weeks.

How is amebiasis diagnosed?

Amebiasis is most commonly diagnosed by examining stool samples under a microscope in a laboratory. Sometimes, several stool samples from several different days must be collected and tested because the number of E. histolytica parasites found in the stool changes from day to day.

What is the treatment for amebiasis?

Specific antibiotics can be prescribed by a doctor to treat amebiasis. People diagnosed with amebiasis, even those who do not have symptoms (carriers), should be treated. People with symptoms are usually treated with two antibiotics (first one and then the other), and those without symptoms are usually treated with one antibiotic.

How can amebiasis be prevented?

The most important precaution is careful hand washing after using the toilet or changing diapers and before preparing or eating food. Avoiding sexual practices that permit fecal-oral contact also reduces risk of disease. When traveling to a country with poor sanitary conditions, use only sealed bottled water, sealed carbonated (bubbly) water or drinks or tap water that has been boiled for at least one minute (at least 10 minutes at high altitudes), and avoid ice and foods that cannot be cooked or peeled.

How long is a person able to spread the disease?

Infected people, often without symptoms, can spread the disease as long as the parasite cysts exist in the stool. This sometimes can continue for years. Generally, it is not necessary to exclude an infected person from work or school.

How can I get more information about amebiasis?

August 2018

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