Insights into chimpanzee parasites have helped show how the most malignant human malaria parasite first infected people.
A DNA study by an international team of scientists shows that the source of the infection made the leap from apes to humans relatively recently.
The findings, based on blood samples from chimpanzees, give new perspective on a mosquito-borne disease that threatens half the world’s population, and causes about 400,000 deaths each year.
Scientists used cutting edge technology to study the genomes of parasites that infect chimpanzees and compared these with the DNA of Plasmodium falciparum, the parasite that causes the deadly form of malaria in people.
They found much more genetic diversity among the chimp parasites, when compared with those infecting humans, indicating that these parasites have infected apes for a much longer time.
This lack of variability in the human parasites suggests that the leap from apes to humans took place relatively recently - perhaps within the past 10,000 years.
Scientists also found evidence that certain key genes jumped from one species of Plasmodium that affects gorillas to another, which later gave rise to the parasite that infects humans.
These genes allow the parasite to invade red blood cells, and this may have enabled infection in people.
The study, published in Nature Communications, was carried out by the Universities of Pennsylvania and Edinburgh with the Sanger Institute. It was funded by the National Institutes of Health.
This aids our understanding of how malaria parasites came to be able to infect people. The more we know about the evolution of this devastating disease, the better equipped we will be to tackle it.