Researchers recently reported artemisinin-resistant Plasmodium falciparum in Pursat province, Cambodia. The international team, led by Rick Fairhurst of the US National Institutes of Health, detected slow parasite clearances rate when patients with falciparum malaria were treated with artesunate — a worrying sign that the parasite may be developing resistance to the frontline treatments for malaria. The findings provide important baseline information about parasite clearance to ongoing longitudinal studies which are monitoring the prevalence of artemisinin resistance and whether resistance is worsening. The study also considered the contribution of parasite genetics and host factors, finding two genetically distinct parasite clonal groups, along with evidence that host factors, such as erythrocyte polymorphisms, affect half-life.
Amaratunga et al. Artemisinin-resistant Plasmodium falciparum in Pursat Province, western Cambodia: a parasite clearance rate study. Lancet Infect Dis. 2012 Nov;12(11):851-8. doi: 10.1016/S1473-3099(12)70181-0. Epub 2012 Aug 30.