Amebiasis (amebic dysentery)

What is amebiasis?

Amebiasis is an intestinal illness caused by a parasite (amoeba) called Entamoeba histolytica.

Who gets amebiasis?

Anyone can get amebiasis, but it is recognized more often in people arriving from tropical or subtropical areas, individuals residing in institutions for the developmentally disabled, and in homosexual males.

How is this parasite spread?

• Amebiasis is contracted by swallowing fecally contaminated food or water containing amebic cysts.
• It can also be spread by person-to-person contact.

What are the symptoms of amebiasis?

People exposed to this parasite may experience mild or severe symptoms or no symptoms at all.

Fortunately, most exposed people do not become seriously ill. The mild form of amebiasis includes:

• Nausea
• Loose stools
• Weight loss
• Abdominal tenderness
• 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 from a few days to a few months after exposure but usually within two to four weeks.

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 which may serve as a vehicle to infect others.
• Animals are not infected with and do not carry the parasite.
• Flies, in some parts of the world, may transfer cysts from human stool to fruits and vegetables.

How is it 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?

Antibiotics are used 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, as casual contact at work or school is unlikely to transmit the disease.

However, food-handlers, childcare workers, or children enrolled in childcare facilities are excluded until they are no longer infected. Special precautions may be needed for individuals residing in institutions for the developmentally disabled.

What precautions should the infected person follow?

• The most important precaution is careful hand washing before eating or preparing food and after each toilet visit.
• Proper disposal of sewage is also important.
• Infected persons should refrain from oral-genital contact until they are effectively treated.

Where can I get more information?

Contact your physician or the Southern Nevada Health District, Office of Epidemiology at (702) 759-1300.