London: Gorillas first transmitted the malaria parasite to humans thousands of years ago, according to a new research.
The latest finding could help develop a vaccine for malaria, which claims 1.5 million lives every year and sickens 500 million more.
It also sheds light on how infectious diseases like HIV, avian and swine flu can be passed on to humans from animals.
Scientists analysed 2,500 primate faeces samples collected in Africa and found DNA evidence of P. falciparum, the parasite that causes malaria in humans, in up to half of those produced by gorillas, reports the Daily Mail.
P. falciparum is the deadliest type of malaria infection, most common in Africa, south of the Sahara, where the World Health Organisation (WHO) says it accounts for the bulk of extremely high mortality.
Weimin Liu of the University of Alabama, US and colleagues said their findings show P. falciparum is of gorilla-origin rather than chimpanzee, bonobo or ancient human as previously thought.
Until recently, the closest known relative of P. falciparum was a chimpanzee parasite P. reichenowi, believed to have diverged from its human counterpart at the same time as the ancestors of chimps and humans more than five million years ago.
Within the past year, other closely related Plasmodium strains have been detected in chimps, western gorillas and bonobos, raising the possibility that P. falciparum in humans could have arisen as a consequence of cross-species transmission from one or more of these apes.