Genetics and malaria control

Malaria currently affects between 300 and 600 million people around the world, according to the WHO. And increasing resistance to anti-malarial drugs means that many countries are experiencing an increasing incidence of the disease. Now, new research carried out simultaneously in Cameroon and Kenya has started to unravel the genetic structure of the parasite by removing it from infected mosquitos.

Assays on short sequences of DNA located on the 14 chromosome pairs of the parasite genome allowed researchers to draw up quite a detailed genetic identity card of the different populations studied. They found an extremely high rate of genetic diversity but also a considerable overall rate of inbreeding, approaching 50%. This high level of inbreeding can be explained by the existence of a process of self-fertilisation, combined with a non-random genotypic distribution of parasite oocysts in the mosquito vector guts. The set of data corroborated those acquired in Kenya in 2005. They confirmed the persistence of a strong population genetic structure of Plasmodium between mosquito vectors, associated with a reproduction regime combining genetic mixing and self fertilisation.

Knowing the genetic identity of Plasmodium populations will help control strategies because researchers will understand the genetics behind drug resistance. This will allow them to target different therapies to different populations, so minimising the evolution of resistance.

This research programme was conducted with the aid of the Kenya Medical Research Institute, the 'Organisation de control contre les endémies en Africa Centrale', the French Ministry of Higher Education and Research and the Institute of evolution and the University of California.