Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Endolimax nana is a single-celled parasite of the colon. Although considered nonpathogenic, infection with E. nana is an indicator of exposure to fecal contamination and often is seen in fecal samples positive for other common parasitic intestinal protists.
E. nana is an intestinal parasitic ameba, which appears to be most closely related to Iodamoeba. , E. nana has a monoxenous life cycle ( Fig. 262.1 ), with trophozoite stages (8–10 μm) found in the colon where they move by pseudopodia, feeding exclusively on bacteria. , The trophozoite nucleus is vesicular and spherical with a polymorphic karyosome ( Fig. 262.2 ). After encystation, the oval cyst (6–9 μm × 5–7 μm) is excreted in feces, and when mature, it contains four nuclei ( Fig. 262.3 ). Mature cysts may excyst and colonize the colon when ingested. When established, the ameba may persist in the colon for ≥17 years.
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here