Common form of malaria has its roots in Africa, study shows

The most widespread form of human malaria originated in Africa – not Asia as was previously thought, new research suggests.

A study of malaria parasites from African primates has enabled researchers to unravel the evolutionary origins of the disease, and could have important implications for efforts to eradicate malaria from human populations.

Their findings explain why almost all natives of central Africa have a genetic mutation that makes them resistant to this type of malaria, even though there had seemed to be no risk of infection in the region.

Researchers studied the DNA of malaria parasites in thousands of faecal samples from wild apes across central Africa. They found a type of malaria parasite that is widespread among chimpanzees and gorillas in the area, which is genetically almost identical to one that affects many millions of people each year across the tropics, apart from in central Africa.

The findings suggest that the parasite, known as Plasmodium vivax, originally affected gorillas, chimps and people in Africa. However, thousands of years ago, people in the region developed a genetic mutation that prevents infection, which spread in central Africa and is still prevalent.

Until now, the closest relatives of this parasite had only been found in Asian primates, leading to the belief that the disease had originated there. The study, published in Nature Communications, was funded by the National Institutes of Health.

This discovery also explains why visitors to Africa can catch this form of malaria – they do not have the resistant mutation, and may be bitten by mosquitoes that have bitten apes. Researchers warn that travellers could pass on ape forms of the parasite in other countries, where they might hybridise with human P. vivax to create new strains.

Professor Paul Sharp, of the University of Edinburgh’s School of Biological Sciences, who led the study, said: “Our new understanding of the origins of this malaria parasite has solved a number of mysteries, and has important implications as efforts to eradicate malaria are intensified.”


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