Entamoeba histolytica

Entamoeba histolytica is an parasitic protozoan, part of the genus "Entamoeba". It infects mainly humans and other primates. 
"E. histolytica" is estimated to infect about 50 million people worldwide. About seventy thousand die each year, mostly from liver abscesses or other complications. The disease it causes is known as amoebiasis. A related species, "Entamoeba dispar", may be even more common.