Researchers have identified what they believe is the original source of malignant malaria: a parasite found in chimpanzees in equatorial Africa. UC Irvine biologist Francisco Ayala and colleagues think the deadly parasite was transmitted to humans from chimpanzees perhaps as recently as 5,000 years ago – and possibly through a single mosquito, genetic analyses indicate. Previously, malaria’s origin had been unclear. This discovery could aid the development of a vaccine for malaria, which sickens about 500 million people and kills about 1.5 million each year. It also furthers understanding of how infectious diseases such as HIV, SARS, and avian and swine flu can be transmitted to humans from animals. The study appears the week of Aug. 3 in the Proceedings of the National Academy of Sciences.