[Entamoeba histolytica (Schaudinn 1903) and Entamoeba dispar (E. Brumpt 1925) are 2 different species].

On the basis of epidemiologic and clinical data in humans, and of experimental studies in kittens, E. Brumpt in 1925 showed that Entamoeba histolytica producing quadrinucleate cysts was a complex of 2 species. He differentiated a pathogenic and invasive form, from a non pathogenic and non invasive one that he called Entamoeba dispar. His explanation gained little support until recently, when Sargeaunt reported a study of isoenzyme typing and allow then the classification of amoebae resembling E. histolytica in pathogenic and non pathogenic species. Monoclonal antibodies and PCR have recently been used and have shown to react specifically with the two forms of amoebae. Genetic evidence has also demonstrated that the pathogenic and non pathogenic amoebae represent different species.