Iodamoeba butschlii

Diagnostic Form:

Cyst and trophozoite forms detected in stool specimens are diagnostic.

Formalin preserved stool concentrates treated with Lugol's Iodine are used to detect the cyst form of the amoeba. The cyst can appear in a few shapes (spherical-oval-tiangular) and can be 5-20 µm in diameter. Mature cysts will contain 1 nucleus. There is no peripheral chromatin to the nucleus and the karyosomal chromatin is large and usually with a eccentric location. The cytoplasm of the cyst does not contain chromatoid body-bars but rather small granules are occasionally seen. A glycogen mass that is compact and well defined is characteristic. This glycogen mass will stain a dark brown with Lugol's Iodine.


Trichrome stained smears can be used to detect cysts and trophozoites in preserved stool specimens. The trophozoites can range between 8-20 µm in length. When a fresh stool is examined directly under the microscope, motility is sluggish and or nearly nonprogressive. The trophozoites contain only one nucleus, that are not visible in unstained preparations, with no peripheral chromatin present. The interior karyosomal chromatin is large, centrally located and surrounded with refractile achromatic granules. The cytoplasm is is coarse; granular; often vacuolated; containing bacteria, yeast, and debris.

shell operculum knob interior


Geographic Prevalence:

The amoeba has a worldwide distribution.


Disease It Causes And The Clinical Symptoms:

The amoeba is not known to cause any disease.


Location In The Host:

Small intestine.


Primary Vector:

None. The amoeba is acquired by ingesting cyst contaminated water or food.


Test Recommended For Detection/Diagnosis:

An ova and parasite examination of the stool is the recommended test for the detection of Iodamoeba butschlii.