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. The goal is to confirm by microscopic examination the
presence of trophozoites or cysts in fecal specimens.
E. histolytica is an obligate parasite of human alimentary tract. It possesses
both cyst and traphozoite forms; trophozoite (12-20 µm in diameter) are microaerophilic
with a granular, vacuolated endoplasm and clear ectoplasm with pseudopods. Please visit
the page about Amebiasis Life Cycle for more information..
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 people are 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 need to 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. |
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