Amebiasis

Amebiasis is invasion of human tissues by the protozoon Entamoeba histolytica. Infection begins when trophozoites of E. histolytica invade the colonic mucosa. The infection may remain localized and be minimal for years, or it may extend to the liver and other organs. What was once thought to be a single species based on morphology is now known to be three genetically distinct species Entamoeba histolytica pathogen, Entamoeba dispar commensal,1 and Entamoeba moshkovskii commensal.2 The free-living amebas that cause meningoencephalitis are discussed in Chapter 9, those infecting other sites are included in this chapter.