ABSTRACT
Entamoeba histolytica infects humans and some higher non-human primates. It is thought to cause an estimated 40 000-100 000 deaths annually. Intestinal infection with E. histolytica – and the associated severe manifestations of invasive amoebiasis – is a global problem, but the true prevalence of the intestinal infection in the northern countries – as indeed globally – is not known. The reason for this is that available prevalence figures, to a large extent, have been based on laboratory findings of ‘E. histolytica cysts’ in faeces. This finding needs to be related to the recent observation that the majority of such cysts can be identified as nonpathogenic Entamoeba dispar. Entamoeba histolytica and E. dispar are morphologically indistinguishable (Diamond and Clark 1993). The two species have previously been called pathogenic and non-pathogenic E. histolytica.
