Very high carriage of gametocytes in asymptomatic low-density Plasmodium falciparum and P. vivax infections in western Thailand

Nguitragool, W; Mueller, I; Kumpitak, C; Saeseu, T; Bantuchai, S; Yorsaeng, R; Yimsamran, S; Maneeboonyang, W; Sa-Angchai, P; Chaimungkun, W; Rukmanee, P; Puangsa-Art, S; Thanyavanich, N; Koepfli, C; Felger, I; Sattabongkot, J; Singhasivanon, P

Author(s): Nguitragool, W; Mueller, I; Kumpitak, C; Saeseu, T; Bantuchai, S; Yorsaeng, R; Yimsamran, S; Maneeboonyang, W; Sa-Angchai, P; Chaimungkun, W; Rukmanee, P; Puangsa-Art, S; Thanyavanich, N; Koepfli, C; Felger, I; Sattabongkot, J; Singhasivanon, P;
Details: Publication Year 2017-10-24,Volume 10,Issue #1,Page 512
Journal Title: Parasites & Vectors
Publication Type: Journal Article
Abstract: BACKGROUND: Low-density asymptomatic infections of Plasmodium spp. are common in low endemicity areas worldwide, but outside Africa, their contribution to malaria transmission is poorly understood. Community-based studies with highly sensitive molecular diagnostics are needed to quantify the asymptomatic reservoir of Plasmodium falciparum and P. vivax infections in Thai communities. METHODS: A cross-sectional survey of 4309 participants was conducted in three endemic areas in Kanchanaburi and Ratchaburi provinces of Thailand in 2012. The presence of P. falciparum and P. vivax parasites was determined using 18S rRNA qPCR. Gametocytes were also detected by pfs25 / pvs25 qRT-PCRs. RESULTS: A total of 133 individuals were found infected with P. vivax (3.09%), 37 with P. falciparum (0.86%), and 11 with mixed P. vivax/ P. falciparum (0.26%). The clear majority of both P. vivax (91.7%) and P. falciparum (89.8%) infections were not accompanied by any febrile symptoms. Infections with either species were most common in adolescent and adult males. Recent travel to Myanmar was highly associated with P. falciparum (OR = 9.0, P = 0.001) but not P. vivax infections (P = 0.13). A large number of P. vivax (71.5%) and P. falciparum (72.0%) infections were gametocyte positive by pvs25/pfs25 qRT-PCR. Detection of gametocyte-specific pvs25 and pfs25 transcripts was strongly dependent on parasite density. pvs25 transcript numbers, a measure of gametocyte density, were also highly correlated with parasite density (r (2) = 0.82, P < 0.001). CONCLUSIONS: Asymptomatic infections with Plasmodium spp. were common in western Thai communities in 2012. The high prevalence of gametocytes indicates that these infections may contribute substantially to the maintenance of local malaria transmission.
Publisher: BioMed Central
Keywords: Malaria; Thailand; Transmission
Research Division(s): Population Health And Immunity
PubMed ID: 29065910
Publisher's Version: https://doi.org/10.1186/s13071-017-2407-y
Open Access at Publisher's Site: https://doi.org/10.1186/s13071-017-2407-y
NHMRC Grants: NHMRC/1043345,
Terms of Use/Rights Notice: Refer to copyright notice on published article.
Documents: Nguitragool et al Parasites Vect_2017.pdf - (0.77MB, application/pdf)

Creation Date: 2018-01-23 10:22:53

Last Modified: 2019-08-13 01:12:57