Geographic distribution. Worldwide in temperate and tropic zone.

Infection rate. Not clear.

Morphology. Trophozoite is smaller than E. histolytica, ranged 5 to 12 ㎛ in diameter, and has a large karyosome, frequently irregular nucleus. Cysts overlap the size range of E. hartmanni, being 8 to 9 ㎛ in diameter. One to four nuclei including the large karyosome are observed.

Pathology and clinical symptoms. Non-pathogenic amoeba.

Diagnosis. Detection of cysts in the stool.

Comments. This amoeba must be distinguished from E. histolytica.

Cyst of Endolimax nana showing 2 nuclei with large karyosome (I-H stain, 1000x).