Therapeutic and Transmission-Blocking Efficacy of Dihydroartemisinin/Piperaquine and Chloroquine against Plasmodium vivax Malaria, Cambodia

We assessed the efficacy of standard 3-day courses of chloroquine and dihydroartemisinin/piperaquine against Plasmodium vivax malaria.Compared with chloroquine, dihydroartemisinin/piperaquine was faster in clearing asexual P. vivax parasites and blocking human-to-mosquito transmission.This drug combination was also more effective in preventing potential recurrences for >2 months.P lasmodium vivax is the most widespread human malaria parasite.Almost 2.5 billion persons are at risk for infection in >90 countries (1,2).Since the 1950s-1960s, Southeast Asia has been the cradle of emergence and spread of P. falciparum antimalarial drug resistance, a major obstacle for malaria control.Over the past decade, control efforts in Cambodia have led to an impressive decrease in malaria burden, with a slower decrease of P. vivax than for P. falciparum (3).P. vivax resistance to chloroquine has emerged more recently; the first cases were observed in 2009 in Rattanakiri Province in northeastern Cambodia (17.4% treatment failures after 28 days of follow-up), which led to withdrawal of chloroquine and use of dihydroartemisinin/piperaquine (DHA/PPQ) as first-line therapy for uncomplicated P. vivax malaria in 2012 (4).We assessed the efficacy of standard 3-day courses of chloroquine and DHA/PPQ for treating P. vivax malaria, preventing recurrences, and blocking human-to-mosquito transmission. The StudyWe conducted an open-label, randomized, control trial in June-December 2014 in Rattanakiri Province, Cambodia.