Ape origins of human malaria

African great apes harbor at least twelve Plasmodium species, some of which have served as a source of human infection. It is now well-established that Plasmodium falciparum emerged following the transmission of a gorilla parasite, perhaps within the last 10,000 years, while Plasmodium vivax emerged from an ancient parasite lineage that infected humans and apes in Africa before the spread of the Duffy-negative mutation eliminated the parasite from humans there. Both human parasites have greatly reduced genetic diversity and a relative excess of nonsynonymous mutations, consistent with severe genetic bottlenecks followed by rapid population expansion. A newly uncovered Plasmodium species widespread in chimpanzees, gorillas and bonobos places the origin of Plasmodium malariae in Africa. Here, we review what is known about the origins and evolutionary history of all human-infective Plasmodium species, the time and circumstances of their emergence, and the diversity, host specificity and zoonotic potential of their ape counterparts.