Malaria may have jumped from chimpanzees to humans much like AIDS and the Ebola virus did, report researchers writing in Proceedings of the National Academy of Sciences.
Analyzing blood samples from nearly 100 chimps in Cameroon and Ivory Coast, Francisco Ayala of the University of California Irvine and colleagues found that an early variant of Plasmodium falciparum, the paraside that causes malayria, may have leapt the species barrier around 10,000 years ago.
“Until now, malaria’s origin had been unclear,” explained a statement from the Global Viral Forecasting Initiative, which was involved in the research. “Although chimpanzees were known to harbor a parasite, called Plasmodium reichenowi, that is closely related to the dominant human malaria parasite, Plasmodium falciparum, most scientists assumed incorrectly that these parasites had co-existed separately in human and chimpanzee ancestors for the last 5 million years.”
“This discovery shows that ancient diseases, such as malaria, can originate in the same way that modern pandemics do, namely by jumping from animals to humans” said Nathan Wolfe of the Global Viral Forecasting Initiative. “We now know that malaria, while at least thousands of years old, did not originate in humans but rather was introduced into our species, presumably by the bite of a mosquito that had previously fed on a chimpanzee.”
“It is now clear that a new disease that successfully jumps from an animal to a human can last not just for decades, but millennia or more,” Wolfe contined. “This makes the task of stopping future disease spillovers from animals to humans vital, not only for saving lives today, but for the health of people for many generations to come.”
The authors hope the findings will help researchers develop new treatments for malaria, which infects 500 million people per year, resulting in more than a million deaths.
Malaria is but one of many diseases that originated in wild animals. A study published last year in the journal Nature found that 60 percent of “disease emergencies” were the result of disease transmission in animals and traveling to humans. AIDS, SARS, Ebola, and swine flu are other examples.