Researchers have shown that the most common form of human malaria originated from infected gorillas.
Their study, published in 'Nature', found a nearly perfect genetic match between the human malaria parasite, Plasmodium falciparum, and those infecting wild gorillas. The finding furthers our understanding about how the parasite adapts to cause disease in humans and could eventually aid efforts to eradicate malaria.
Researchers from the University of Alabama at Birmingham, the Wellcome Trust Sanger Institute and colleagues analysed over 2700 ape faecal samples collected from 57 field sites throughout central Africa.
The researchers found that Plasmodium infection was widespread, with up to half of the apes in some communities infected. It is not currently known whether infection with the parasite causes malaria-like disease in apes.
Using techniques developed for HIV analysis, the researchers identified the malaria parasites infecting the apes. The findings showed that wild-living Western gorillas were the source of human P. falciparum, though when this jump occurred remains a mystery. Whether apes are still a source for ongoing human infection also remains unknown. The researchers are looking for further clues by screening humans who live in close proximity to wild apes.
"Understanding where a human pathogen, like Plasmodium falciparum, originated can be an important step in learning how to prevent and treat the disease that it causes," said Dr Beatrice Hahn from the University of Alabama, who led the research.
"Like AIDS, malaria is of primate origin. Studies of the primate precursors of HIV have unravelled many aspects of AIDS pathogenesis. I expect the same to happen when the biology of the gorilla precursor of P. falciparum is compared to that of its human counterpart."
The discovery contradicts earlier studies indicating that the origins of malaria lay in chimpanzees and bonobo apes. However, the researchers say these studies only analysed a few apes, mostly held in captivity. Their new study is more comprehensive and is based on samples collected in the wild.
Source: Wellcome Trust news release
Reference: Liu W et al. Origin of the human malaria parasite Plasmodium falciparum in western gorillas. Nature 2010.