Spread of a single multidrug resistant malaria parasite lineage (PfPailin) to Vietnam
The spread of artemisinin resistance in
Plasmodium falciparum and the subsequent loss of partner antimalarial drugs in the Greater Mekong subregion1 presents one of the greatest threats to the control and elimination of malaria. Artemisinin resistance is associated with mutations in the
PfKelch gene. Initially multiple independent
Kelch mutations were observed, but in a recent sinister development, a single dominant artemisinin-resistant
P falciparum C580Y mutant lineage has arisen in western Cambodia, outcompeted the other resistant malaria parasites, and subsequently acquired resistance to piperaquine. Cambodia had adopted dihydroartemisinin-piperaquine as first-line antimalarial treatment, but has now been forced to switch its first line artemisinin combination treatment back to artesunate-mefloquine as a consequence. This dominant multidrug-resistant parasite lineage, identified first in Pailin in western Cambodia and tentatively denoted as
PfPailin, then spread to northeastern Thailand and southern Laos. We now find that the
PfPailin lineage, with associated piperaquine resistance (evidenced by amplification in the
PfPlasmepsin gene), has spread to the south of Vietnam where it is responsible for alarming rates of failure of dihydroartemisinin-piperaquine—the National first-line treatment (
figure). Microsatellite typing of 86 of 152
P falciparum isolates from the Binh Phuoc locality in 2016 shows the same flanking sequence surrounding the
PfKelch C580Y gene as that observed in parasites from the affected areas of the other three Greater Mekong subregion countries.2 The evolution and subsequent transnational spread of this single fit multidrug-resistant malaria parasite lineage is of international concern.
