Until recently, it was believed that P. vivax originated in Asia, as its closest genetic relatives were found only in Asian macaques. But in a study published in Nature Communications, an international research team found evidence that wild- living apes in Central Africa are widely infected with parasites that are nearly identical, genetically, to human P. vivax.
After testing more than 5,000 ape fecal samples from across Africa, the scientists found P. vivax-like sequences in chimps and western and eastern gorillas. A comparison of the DNA sequences of the human and ape parasites led the team to conclude that all existing human P. vivax parasites evolved from a single ancestor that spread out of Africa.
The study has helped to resolve a puzzling anomaly relating to human P. vivax infection. Although the parasite is absent from West and Central Africa, a genetic mutation that confers resistance to P. vivax is common among people who live there. It was suspected that P. vivax malaria was the agent that selected for this mutation, but it was difficult to reconcile this with the belief that P. vivax originated in Asia.
This story was published in the April 2014 edition of Geographical Magazine