Cristian KoepfliWang NguitragoolAnne Cristine Gomes de AlmeidaAndrea KuehnAndreea WaltmannEline KattenbergMaria Ome-KaiusPatricia RarauThomas ObadiaJames KazuraWuelton MonteiroAndrew W. DarcyLyndes WiniQuique BassatIngrid FelgerJetsumon SattabongkotLeanne J. RobinsonMarcus LacerdaIvo MuellerFaculty of Tropical Medicine, Mahidol UniversityCentro de Investigación Biomédica en Red de Epidemiología y Salud PúblicaPapua New Guinea Institute of Medical ResearchInstitució Catalana de Recerca i Estudis AvançatsWalter and Eliza Hall Institute of Medical ResearchUniversity of MelbourneSwiss Tropical and Public Health Institute (Swiss TPH)University of Notre DameCASE School of MedicineUniversidade do Estado do AmazonasInstitut Pasteur, ParisUniversitat de BarcelonaMinistry of HealthCentro de Investigação em Saúde de Manhiça (CISM)Fundação de Medicina Tropical Dr. Heitor Vieira Dourado2022-08-042022-08-042021-08-01PLoS Neglected Tropical Diseases. Vol.15, No.8 (2021)19352735193527272-s2.0-85114108652https://repository.li.mahidol.ac.th/handle/20.500.14594/77982Background Understanding epidemiological variables affecting gametocyte carriage and density is essential to design interventions that most effectively reduce malaria human-to-mosquito transmission. Methodology/Principal findings Plasmodium falciparum and P. vivax parasites and gametocytes were quantified by qPCR and RT-qPCR assays using the same methodologies in 5 cross-sectional surveys involving 16,493 individuals in Brazil, Thailand, Papua New Guinea, and Solomon Islands. The pro-portion of infections with detectable gametocytes per survey ranged from 44–94% for P. fal-ciparum and from 23–72% for P. vivax. Blood-stage parasite density was the most important predictor of the probability to detect gametocytes. In moderate transmission settings (prevalence by qPCR>5%), parasite density decreased with age and the majority of gametocyte carriers were children. In low transmission settings (prevalence<5%), >65% of gametocyte carriers were adults. Per survey, 37–100% of all individuals positive for gameto-cytes by RT-qPCR were positive by light microscopy for asexual stages or gametocytes (overall: P. falciparum 178/348, P. vivax 235/398). Conclusions/Significance Interventions to reduce human-to-mosquito malaria transmission in moderate-high endemicity settings will have the greatest impact when children are targeted. In contrast, all age groups need to be included in control activities in low endemicity settings to achieve elimination. Detection of infections by light microscopy is a valuable tool to identify asymp-tomatic blood stage infections that likely contribute most to ongoing transmission at the time of sampling.Mahidol UniversityMedicineArticleSCOPUS10.1371/journal.pntd.0009672