Malignant malaria found in gorillas

A study or gorilal faeces has revealed that they carry malaria. Photo credit Wildlife Extra

January 2010. The parasite that causes malignant malaria in humans has been detected in gorillas, along with two new species of malaria parasites, according to a new study co-authored by biologist Francisco Ayala.

Malaria originated in chimpanzees
The study also confirms a recent discovery by Ayala and colleagues that human malignant malaria, caused by Plasmodium falciparum, originated from a closely related parasite found in chimpanzees in equatorial Africa. P. falciparum is responsible for 85 percent of malignant malaria infections in humans and nearly all deaths from the disease.

Greater contact with apes creates greater risk for apes and humans
The researchers cautioned that increased contact between primates and humans - mostly because of logging and deforestation - creates a greater risk of new parasites being transmitted to humans. It also could further jeopardize endangered ape populations by spreading diseases to them. Finding P. falciparum in gorillas also complicates the challenge of eradicating malaria.

The researchers cautioned that increased contact between primates and humans - mostly because of logging and deforestation - creates a greater risk of new parasites being transmitted to humans.

Apes provide pool of infection
"Hundreds of billions of dollars are spent each year on trying to rid humans of malignant malaria. But success may be a pyrrhic victory, because we could be re-infected by gorillas - just as we were originally infected by chimps a few thousand years ago," said Ayala, corresponding author of the study, published this week in the Proceedings of the National Academy of Sciences.

Chimps and gorilla faeces tested
The researchers analyzed faecal samples from 125 wild chimpanzees and 84 gorillas in Cameroon and tested blood samples from three gorillas in Gabon. They identified two new closely related species of malaria parasites - Plasmodium GorA and Plasmodium GorB - that infect gorillas. The animals also were found to harbour P. falciparum, previously thought to only infect humans.

All malaria in humans started by 1 mosquito?
In August 2009, Ayala and colleagues published a study reporting that P. falciparum had been transmitted to humans from chimpanzees perhaps as recently as 5,000 years ago - and possibly through a single mosquito. Before then, malaria's origin had been unclear.

Chimpanzees were known to carry the parasite Plasmodium reichenowi, but most scientists assumed the two parasites had existed separately in humans and chimpanzees for the last 5 million years.

The discovery could aid the development of a vaccine for malaria, which each year causes 2 million infant deaths and sickens about 500 million people, mostly in sub-Saharan Africa. It also furthers understanding of how infectious diseases such as HIV, SARS, and avian and swine flu can be transmitted to humans from animals.