What Is Amebiasis?
What is amebiasis?
Amebiasis is a disease caused by a one-celled parasite called Entamoeba
histolytica (ent-a-ME-ba his-to-LI-ti-ka).
Who is at risk for amebiasis?
Although anyone can have this disease, it is most common in people who live
in developing countries that have poor sanitary conditions. In the United
States, amebiasis is most often foundin immigrants from developing countries.
It also is found in people who have traveled to developing countries and in
people who live in institutions that have poor sanitary conditions. Men who
have sex with men can become infected and can get sick from the infection, but
they often do not have symptoms.
How can I become infected with E. histolytica?
- By putting anything into your mouth that has touched the stool of a person
who is infected with E. histolytica.
- By swallowing something, such as water or food, that is contaminated with
- By touching and bringing to your mouth cysts (eggs) picked up from surfaces
that are contaminated with E. histolytica.
What are the symptoms of amebiasis
On average, about one in 10 people who are infected with E.
histolytica becomes sick from the infection. The symptoms often are quite
mild and can include loose stools, stomach pain, and stomach cramping. Amebic
dysentery is a severe form of amebiasis associated with stomach pain, bloody
stools, and fever. Rarely, E. histolytica invades the liver and forms
an abscess. Even less commonly, it spreads to other parts of the body, such as
the lungs or brain.
If I swallowed E. histolytica, how quickly would I become sick?
Usually 1 to 4 weeks later but sometimes more quickly or more slowly.
What should I do if I think I have amebiasis?
See your health care provider.
How is amebiasis diagnosed?
Your health care provider will ask you to submit stool samples. Because
E. histolytica is not always found in every stool sample, you may be
asked to submit several stool samples from several different days.
Diagnosis of amebiasis can be very difficult. One problem is that other
parasites and cells can look very similar to E. histolytica when seen
under a microscope. Therefore, sometimes peopleare told that they are infected
with E. histolytica even though they are not. Entamoeba
histolytica and another amoeba, Entamoeba dispar, which is about
10 times more common, look the same when seen under a microscope. Unlike
infection with E. histolytica, which sometimes makes people sick,
infection with E. dispar never makes people sick and therefore does
not needto be treated.
If you have been told that you are infected with E. histolytica but
you are feeling fine, you might be infected with E. dispar instead.
Unfortunately, most laboratories do not yet have the tests that can tell
whether a person is infected with E. histolytica or with E.
dispar. Until these tests become more widely available, it usually is best
to assume that the parasite is E. histolytica.
A blood test is also available. However, the test is recommended only when
your health care provider thinks that your infection has invaded the wall of
the intestine (gut) or some other organ of your body, such as the liver. One
problem is that the blood test may still be positive if you had amebiasis in
the past, even if you are no longer infected now.