Researchers report original source of malaria found

UC Irvine Researchers have identified what they believe is the original source of malignant malaria in equatorial Africa.

Biologist Francisco Ayala and colleagues think the deadly parasite was transmitted to humans from chimpanzees perhaps as recently as 5,000 years ago. Genetic analyses indicate the transmission could have been through one mosquito. Prior to this study malaria's origin was uncertain. "When malaria transferred to humans, it became very severe very quickly," said Ayala, co-author of the study that reports these findings. "The disease in humans has become resistant to many drugs. It's my hope that our discovery will bring us closer to making a vaccine." The study appears online the week of Aug. 3 in the Proceedings of the National Academy of Sciences. A parasite called Plasmodium falciparum causes human malignant malaria. Human malignant malaria is responsible for 85 percent of all infections and nearly all malaria deaths. It was widely known chimpanzees carried a closely related parasite called Plasmodium reichenowi, however,scientists, generally assumed, the two had existed separately in humans and chimpanzees for the last 5 million years. As humans moved into chimpanzee territory, the closer contact made transmission simpler. Deforestation helped create more mosquito breeding grounds and thus more mosquitoes. "Today, human encroachment into the last forest habitats has further extended, leading to a higher risk of transfer of new pathogens, including new malaria parasites," the researchers warn.