Gene clues point to Cambodia for resistant Malaria

FRANCE: Gene analysis of malaria parasites has pinpointed western Cambodia as the hotspot of strains that are dangerously resistant to artesiminin, the frontline drug against the disease, scientists said on Sunday.

An international consortium of researchers unravelled the genetic code of 825 samples of the Plasmodium falciparum parasite from Burkina Faso, Gambia, Ghana, Mali, Thailand, Vietnam and from northeastern and western Cambodia.

The 166 samples from western Cambodia stood out, the team reported in the journal Nature Genetics.

Included in them were three sub-populations of parasites whose genetic mutations made them resistant to artesiminin. These strains appear to be the wellspring for malarial resistance that is spreading to other countries.

"Clinical resistance to artemisinin and its derivatives is now well established in the P. falciparum population of western Cambodia and appears to be emerging in neighbouring regions," said the paper. "These recent developments have grave implications for public health, as artemisinin derivatives are the mainstay of malaria treatment worldwide." Western Cambodia has unleashed "successive global waves" of antimalarial drug resistance, the investigators said. Resistance to chloroquine drugs was observed there in the late 1950s before it spread around the world, and the most common forms of resistance to pyrimethamine and sulfadoxine drugs are also thought to have originated there. The study offers several reasons why such a relatively small geographical area should be so unusual. Parasites are transmitted to humans by Anopheles mosquitoes, and a crucial step in the process is the way in which the parasites swap genes within mosquito.

AFP