Malaria kills more than a million people every year. Recently, an international team of biologists used genetic techniques to trace how the malaria parasite Plasmodium falciparum first emerged to infect humans. In their study of chimpanzees in West Africa, the researchers discovered that P. falciparum evolved from Plasmodium reichenowi, a species of chimpanzee malaria. Malaria thus began much like many other modern pandemics such as HIV, SARS, and swine flu—it jumped from animals to humans.