By Doreen Walton
Science reporter, BBC News
The malaria parasite was found in a sample from the cross river gorillla
The parasite which causes malignant malaria in humans has been identified in gorillas for the first time.
Researchers analysed faeces from wild gorillas in Cameroon and blood samples from a captive animal from Gabon.
The study says increasing contact between humans and primates due to logging and deforestation raises the risk of transmission of new pathogens.
The research findings are published in Proceedings of the National Academy of Sciences journal.
New genetic sampling techniques allowed scientists from France, Cameroon, Gabon and the US to examine evidence of malaria parasites in the faecal matter of wild gorillas and chimpanzees in Cameroon.
"Sampling malaria parasites from apes in the wild has until now been very difficult", said Dr Francisco Ayala from the University of California, Irvine.
The team also took blood samples from wild born, pet animals in Gabon.
DNA evidence of Plasmodium falciparum, the parasite that causes malignant malaria in humans, was found in faecal samples from two gorilla subspecies, the highly endangered cross-river gorilla and the western lowland gorilla.
The parasite was identified in a blood sample from a captive gorilla.
Malaria parasites were first identified in chimpanzees and gorillas in Africa by scientists working in the 1920s.
But this new technology has allowed scientists to confirm the presence of P. falciparum.
P. falciparum is the most deadly type of malaria infection.
It is most common in Africa, south of the Sahara, where the World Health Organization says it accounts for a large part of the extremely high mortality in the region.
The study says that human destruction of the natural forest habitat means more contact with primates and greater chances of pathogen transmission between the two, including from humans to the endangered great apes.
Dr Ayala said the findings underline the danger of contact between the two. "Even if it were eradicated in humans we would still have the problem that it's present in apes and therefore they would be a reservoir for the disease.
"It's not clear what we can do with respect to this problem other than trying to decrease contact."
Dr Ian Hastings, senior lecturer at the Liverpool School of Medicine said it would help to know more about the spread of the parasite in gorillas.
"Mosquitoes often bite different species. Often they have a preference but if they can't find what they want to bite they'll just go and bite something else," he said.
"The question is whether this is just sporadic infection that's come from humans after the mosquito bit an infected person and passed it on to gorillas or whether it's endemic and is passed from gorilla to gorilla."
Dr Ayala acknowledges that Plasmodium parasites are much less malignant for apes than humans because primates have been exposed to them for so long.
"They have had P. reichenowi and perhaps other species for thousands or millions of generations, so one expects less malignancy to have taken place over time."