Following the path of most resistance: dhps K540E dispersal in African Plasmodium falciparum.

Chloroquine resistant malaria (CQR) emerged in East Africa during the late 1970s and then spread westward. A molecular marker only became available in the late 1990s, and by that time CQR had permeated throughout Africa. By contrast, resistance to sulphadoxine-pyrimethamine (SPR) has emerged during an era of molecular surveillance, and the changing prevalence of SPR conferred by point mutations in the dhfr and dhps genes has been recorded in hundreds of sites across Africa. We have collated and mapped reports of the dhps K540E mutation, a uniquely informative marker of SPR, and used these to describe the geography of its dispersal through time. Like CQR, dhps K540E appeared first in East Africa and spread west. We discuss whether there are common principles governing resistance dispersal in Africa and how these might guide surveillance in future.