Malaria jumped to humans from chimpanzees at some point in the last two million years:
After gathering blood samples from nearly 100 chimpanzees in central Africa, researchers uncovered eight new strains of the parasite that causes chimp malaria. By comparing genes from the new chimp strains to genes from human malaria, scientists discovered that like HIV, our malaria bug is a gift from chimpanzees.“The conventional wisdom on malaria is that this is a disease that has been in humans since the dawn of humanity,” said infectious disease expert Nathan Wolfe of Stanford University, who co-authored the paper published Monday in the Proceedings of the National Academy of Sciences. “In fact, what we found was really quite surprising to us: There is a tremendous diversity of these parasites in chimpanzees, and it’s a diversity that completely encompasses a much more limited diversity in human malaria.”
“There’s only one way to interpret that finding,” Wolfe said. “Namely, that this is a chimpanzee parasite that had jumped over to human populations.”
[...]
The researchers think chimpanzee malaria was probably carried to humans by mosquitoes. And although the main transmission event happened only once, Wolfe thinks that in some remote areas, there could be an ongoing exchange of parasites between humans and chimps.
Clearly then our only course of action is to exterminate all chimps — in self-defense. Right?