Gorillas in midst of malaria mystery

[By Nicky Phillips, Sydney Morning Herald, September 26, 2010]

[Host to killer pathogen ... a silverback gorilla forages in the Republic of Congo. Photo: National Geographic Society]

A PARASITE that causes malaria may have originated in gorillas, a study has found. The pathogen, Plasmodium falciparum, is the most widespread and lethal of the malaria parasites that infect humans.
The research will give scientists important insights into eradicating the mosquito-borne disease, which is contracted by more than 250 million people a year and kills nearly 1 million.

Previous research had suggested the human malaria parasite split from a chimpanzee parasite when humans and chimpanzees last had a common ancestor.

Other studies claimed the pest originated in bonobos, or possibly a human ancestor.

To determine the source of the parasite, researchers gathered faecal samples from chimpanzees, bonobos and eastern and western gorillas in central Africa. No parasites were found in bonobos or eastern gorillas, but about half the western gorillas and chimpanzees were infected. When the researchers analysed the DNA strain, they found the parasites were closely related to the parasite that infects humans.

This suggested the parasite jumped from gorillas to humans, the researchers said.

The scientists do not know when the cross from gorillas to humans occurred, or whether the parasite has a negative impact on apes.

"What is still unclear is . . . whether present-day ape populations represent a source for recurring humans infections," said the researchers, whose findings are published in the journal Nature.

The findings will inform scientists and health experts about how the parasite has evolved and adapted and the possible reservoirs of the parasite, which will, in turn, aid malaria eradication efforts.

Malaria is a serious problem, especially in Africa, where one in every five childhood deaths is due to the effects of the disease.