Iodamoeba bütschlii (Nonpathogen)

Organism:
This organism belongs to the amebae, is a nonpathogen, and causes no disease.  Both the trophozoite (usual size, 8-20 µm) and cyst forms (usual size, 5-20 µm) can be found in clinical specimens.

Trophozoite                             Cysts in iodine                             Cysts, stained

Life Cycle:
Intestine, organisms passed in feces

Acquired:
Fecal-oral transmission via cyst form; contaminated food and water

Epidemiology:
Worldwide, primarily human-to-human transmission

Clinical Features:
None

Clinical Specimen:
Intestinal:  Stool

Laboratory Diagnosis:
Intestinal:  Ova and Parasite examination (concentration, permanent stained smear); identification based on morphology

Organism Description:
Trophozoite:  No nuclear chromatin, large karyosome, relatively messy cytoplasm (may contain some debris and vacuoles); (can mimic Endolimax nana).
Cyst:  Will contain large glycogen vacuole (may collapse on itself), mature cyst contains 1 nucleus; peripheral nuclear chromatin often seen on one side “basket nucleus” – nucleus contains large karyosome that appears a brown in an iodine stain.

Laboratory Report:
Iodamoeba bütschlii (indicate cysts and/or trophozoites)

Treatment:
None

Control:
Improved hygiene, adequate disposal of fecal waste, adequate washing of contaminated fruits and vegetables

Comments:
I. bütschlii trophozoites can be very difficult to differentiate from those of E. nana.