Entamoeba coli can be found worldwide.It is a non pathogenic species of Entamoeba causing Intestinal amebiasis, amebic colitis, amebic dysentery, extraintestinal amebiasis.It’s occurs in cold climates, such as Alaska, as well as warm climates.Geographic areas with poor hygiene and sanitation practices are at the greatest risk of becoming endemic with Entamoeba coli.As with the other intestinal amebas, Entamoeba coli is transmitted by ingestion of the infected cyst through contaminated food or drink.
Morphology of Entamoeba coli
Trophozoites of Entamoeba coli
Entamoeba coli trophozoites typically measure between 18 and 27 μm.Some trophozoites may be as small as 12 μm, while others may be as large as 55 μm.The trophozoite is equipped with blunt pseudopods and exhibits sluggish, non – progressive motility.The single nucleus can be easily recognized.The karyosome and surrounding peripheral chromatin appear as refractile structures in unstained preparations.When trophozoites are stained, the nuclear structures are enhanced.The typical nucleus consists of an eccentrically located large, often irregularly shaped karyosome.The karyosome is surrounded by unevenly distributed peripheral chromatin, which varies in size and becomes apparent with the addition of stain.In some cases, chromatin granules can be visible in the area between the karyosome and the peripheral chromatin.Nuclear variations similar to those of Entamoeba histolytica and Entamoeba hartmanni may also occur in Entamoeba coli trophozoites.Vacuoles, often containing bacteria, are commonly seen in the heavily granulated cytoplasm.In contrast to Entamoeba histolytica, red blood cell inclusions are not present in Entamoeba coli trophozoites.
Cysts of Entamoeba coli
Entamoeba coli cysts vary in size from 8 to 35 μm and an average of 12 to 25 μm.A thick cell wall surrounds the round to spherical cyst.The cyst nuclei are readily discernible, as with the trophozoite.One to eight nuclei with the typical nuclear characteristics can be seen in both unstained and stained preparations.Occasionally there may be large cysts containing 16 or more nuclei.Young cysts ‘ granular cytoplasm may contain a glycogen mass.Occasionally, the glycogen mass may displace the nuclei present at opposite ends of the cyst, a variation often seen in cysts with two nuclei present.Thin chromatoidal bars, often with splintered ends, may also be contained in the cytoplasm of young cysts.
Clinical symptoms of Entamoeba coli infection
As with infections of Entamoeba hartmanni, infections with Entamoeba coli are usually asymptomatic.
How is amebiasis diagnosed?
Stool examination is the method of choice for recovering Entamoeba coli trophozoites and cysts.Although not considered pathogenic, the presence of Entamoeba coli suggests ingestion of contaminated food or drink.Therefore, in addition to the non pathogenic Entamoeba coli, laboratory technicians should carefully examine these preparations for the presence of pathogenic parasites.
How is Entamoeba coli treated?
Entamoeba coli is considered a non – pathogen. Therefore, treatment is usually not indicated.
Prevention and Control of entamoeba coli
Adequate disposal of human feces and proper personal hygiene practices are critical to preventing Entamoeba coli infections. Protection of food and drink from flies and cockroaches is also necessary to break the cycle of transmission of Entamoeba coli.