TY - JOUR
T1 - Identification of the asymptomatic Plasmodium falciparum and Plasmodium vivax gametocyte reservoir under different transmission intensities
AU - Koepfli, Cristian
AU - Nguitragool, Wang
AU - de Almeida, Anne Cristine Gomes
AU - Kuehn, Andrea
AU - Waltmann, Andreea
AU - Kattenberg, Eline
AU - Ome-Kaius, Maria
AU - Rarau, Patricia
AU - Obadia, Thomas
AU - Kazura, James
AU - Monteiro, Wuelton
AU - Darcy, Andrew W
AU - Wini, Lyndes
AU - Bassat, Quique
AU - Felger, Ingrid
AU - Sattabongkot, Jetsumon
AU - Robinson, Leanne J
AU - Lacerda, Marcus
AU - Mueller, Ivo
N1 - FTX; DOAJ
PY - 2021
Y1 - 2021
N2 - BACKGROUND: 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 proportion of infections with detectable gametocytes per survey ranged from 44-94% for P. falciparum 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 gametocytes 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 asymptomatic blood stage infections that likely contribute most to ongoing transmission at the time of sampling.
AB - BACKGROUND: 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 proportion of infections with detectable gametocytes per survey ranged from 44-94% for P. falciparum 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 gametocytes 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 asymptomatic blood stage infections that likely contribute most to ongoing transmission at the time of sampling.
U2 - 10.1371/journal.pntd.0009672
DO - 10.1371/journal.pntd.0009672
M3 - A1: Web of Science-article
C2 - 34449764
SN - 1935-2727
VL - 15
JO - PLoS Neglected Tropical Diseases
JF - PLoS Neglected Tropical Diseases
IS - 8
M1 - e0009672
ER -