Endolimax nana

Morphology, life cycle, diagnosis, symptoms, and treatment.

1. Endolimax nana Prepared by: Veronica Baje

2. Endolimax nana Endolimax is a genus of amoebozoa that are found in the intestines of various animals, including the species E. nana found in humans. Originally thought to be non-pathogenic, studies suggest it can cause intermittent or chronic diarrhea. Additionally, it is very significant in medicine because it can provide false positives for other tests, notably the similar species Entamoeba histolytica, the pathogen responsible for amoebic dysentery, and because its presence indicates the host has consumed fecal material.

3. Trophozoites Vary in size from 5 to 12 μ m. The average trophozoite size range is 7 to 10 μ m. Sluggish, nonprogressive motility, which is accomplished by blunt, hyaline pseudopods. Single nucleus may or may not be visible in unstained preparations. Karyosome is large and irregularly shaped. Blotlike appearance.

4. Cysts Spherical, ovoid, or ellipsoid cysts Measures 7 to 10 μ m in size. Some cysts may measure a mere 4 μ m, whereas others may be as large as 12 μ m. There may be one to four nuclei in an E. nana cyst, the most commonly seen form is the mature cyst that contains 4 nuclei.

5. Life Cycle  Cysts are typically found in formed stool, whereas trophozoites are typically found in diarrheal stool. Intestinal colonization with nonpathogenic amebae occurs after ingestion of mature cysts in fecally contaminated food, water, or fomites. Excystation occurs in the small intestine  and trophozoites are released, which migrate to the large intestine. The trophozoites multiply by binary fission and produce cysts, and both stages are passed in the feces 

6. Clinical Symptoms E. nana infections are usually asymptomatic.

7. Laboratroy Diagnosis The laboratory diagnostic technique of choice for identifying E. nana trophozoites and cysts is stool examination.

8. Treatment E. nana is considered a nonpathogen. Treatment is generally not indicated.