Nicholas M. DouglasJulie A. SimpsonAung Pyae PhyoHadjar SiswantoroArmedy R. HasugianEnny KenangalemJeanne Rini PoespoprodjoPratap SinghasivanonNicholas M. AnsteyNicholas J. WhiteEmiliana TjitraFrancois NostenRic N. PriceMenzies School of Health ResearchNuffield Department of Clinical MedicineUniversity of MelbourneShoklo Malaria Research UnitBadan Penelitian Dan Pengembangan Kesehatan, Kementerian Kesehatan Republik IndonesiaMimika District Health AuthorityNational Institutes of Health, BethesdaMahidol UniversityRoyal Darwin Hospital2018-10-192018-10-192013-09-01Journal of Infectious Diseases. Vol.208, No.5 (2013), 801-812002218992-s2.0-84881649097https://repository.li.mahidol.ac.th/handle/20.500.14594/32196Background. Designing interventions that will reduce transmission of vivax malaria requires knowledge of Plasmodium vivax gametocyte dynamics.Methods. We analyzed data from a randomized controlled trial in northwestern Thailand and 2 trials in Papua, Indonesia, to identify and compare risk factors for vivax gametocytemia at enrollment and following treatment.Results. A total of 492 patients with P. vivax infections from Thailand and 476 patients (162 with concurrent falciparum parasitemia) from Indonesia were evaluable. Also, 84.3% (415/492) and 66.6% (209/314) of patients with monoinfection were gametocytemic at enrollment, respectively. The ratio of gametocytemia to asexual parasitemia did not differ between acute and recurrent infections (P =. 48 in Thailand, P =. 08 in Indonesia). High asexual parasitemia was associated with an increased risk of gametocytemia during follow-up in both locations. In Thailand, the cumulative incidence of gametocytemia between day 7 and day 42 following dihydroartemisinin + piperaquine (DHA + PIP) was 6.92% vs 29.1% following chloroquine (P <. 001). In Indonesia, the incidence of gametocytemia was 33.6% following artesunate + amodiaquine (AS + AQ), 7.42% following artemether + lumefantrine, and 6.80% following DHA + PIP (P <. 001 for DHA + PIP vs AS + AQ).Conclusions. P. vivax gametocyte carriage mirrors asexual-stage infection. Prevention of relapses, particularly in those with high asexual parasitemia, is likely the most important strategy for interrupting P. vivax transmission. © 2013 The Author.Mahidol UniversityMedicineArticleSCOPUS10.1093/infdis/jit261