Rupam TripuraPeto, Thomas J.Jeremy ChalkLee, Sue J.Pasathorn SirithiranontChea NguonMehul DhordaSeidlein, Lorenz vonMaude, Richard J.Day, Nicholas P. J.Mallika ImwongWhite, Nicholas J.Dondorp, Arjen M.Mahidol University. Faculty of Tropical Medicine. Mahidol-Oxford Tropical Medicine Research Unit2017-11-152017-11-152017-11-152016Malaria Journal. Vol.15, (2016), 181https://repository.li.mahidol.ac.th/handle/123456789/3149Background: Subclinical Plasmodium parasitaemia is an important reservoir for the transmission and persistence of malaria, particularly in low transmission areas. Methods: Using ultrasensitive quantitative PCR (uPCR) for the detection of parasitaemia, the entire population of three Cambodian villages in Pailin province were followed for 1 year at three-monthly intervals. A cohort of adult participants found initially to have asymptomatic malaria parasitaemia was followed monthly over the same period. Results: The initial cross sectional survey in June 2013 (M0) of 1447 asymptomatic residents found that 32 (2.2 %) had Plasmodium falciparum, 48 (3.3 %) had P. vivax, 4 (0.3 %) had mixed infections and in 142/1447 (9.8 %) malaria was detected but there was insufficient DNA to identify the species (Plasmodium. species). Polymorphisms in the ‘K13-propeller’ associated with reduced susceptibility to artemisinin derivatives (C580Y) were found in 17/32 (51 %) P. falciparum strains. Monthly follow-up without treatment of 24 adult participants with asymptomatic mono or mixed P. falciparum infections found that 3/24 (13 %) remained parasitaemic for 2–4 months, whereas the remaining 21/24 (87 %) participants had cleared their parasitaemia after 1 month. In contrast, 12/34 (35 %) adult participants with P. vivax mono-infection at M0 had malaria parasites (P. vivax or P. sp.) during four or more of the following 11 monthly surveys. Conclusions: This longitudinal survey in a low transmission setting shows limited duration of P. falciparum carriage, but prolonged carriage of P. vivax infections. Radical treatment of P. vivax infections by 8-aminoquinoline regimens may be required to eliminate all malaria from Cambodia. Trial registration ClinicalTrials.gov NCT01872702engMahidol UniversityOpen Access articleMalariaPersistenceCohortPlasmodiumFalciparumVivaxClearanceArtemisininsResistancePailinCambodiaPCRResearch ArticleBioMed Central10.1186/s12936-016-1224-7