Publication: The epidemiology of subclinical malaria infections in South‑East Asia: findings from cross‑sectional surveys in Thailand– Myanmar border areas, Cambodia, and Vietnam
Issued Date
2015
Resource Type
Language
eng
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Mahidol University
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BioMed Central
Bibliographic Citation
Malaria Journal. Vol.14, (2015), 381
Suggested Citation
Mallika Imwong, Nguyen, Thuy Nhien, Rupam Tripura, Peto, Tom J., Lee, Sue J., Lwin, Khin Maung, Preyanan Suangkanarat, Atthanee Jeeyapant, Benchawan Vihokhern, Klanarong Wongsaen, Hue, Dao Van, Dong, Le Thanh, Nguyen, Tam‑Uyen, Yoel Lubell, Seidlein, Lorenz von, Mehul Dhorda, Cholrawee Promnarate, Georges Snounou, Benoit Malleret, Laurent Rénia, Lilly Keereecharoen, Pratap Singhasivanon, Pasathorn Sirithiranont, Jem Chalk, Chea Nguon, Hien, Tran Tinh, Nicholas Day, White, Nicholas J., Arjen Dondorp, Francois Nosten The epidemiology of subclinical malaria infections in South‑East Asia: findings from cross‑sectional surveys in Thailand– Myanmar border areas, Cambodia, and Vietnam. Malaria Journal. Vol.14, (2015), 381. doi:10.1186/s12936-015-0906-x Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/3086
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Title
The epidemiology of subclinical malaria infections in South‑East Asia: findings from cross‑sectional surveys in Thailand– Myanmar border areas, Cambodia, and Vietnam
Author(s)
Mallika Imwong
Nguyen, Thuy Nhien
Rupam Tripura
Peto, Tom J.
Lee, Sue J.
Lwin, Khin Maung
Preyanan Suangkanarat
Atthanee Jeeyapant
Benchawan Vihokhern
Klanarong Wongsaen
Hue, Dao Van
Dong, Le Thanh
Nguyen, Tam‑Uyen
Yoel Lubell
Seidlein, Lorenz von
Mehul Dhorda
Cholrawee Promnarate
Georges Snounou
Benoit Malleret
Laurent Rénia
Lilly Keereecharoen
Pratap Singhasivanon
Pasathorn Sirithiranont
Jem Chalk
Chea Nguon
Hien, Tran Tinh
Nicholas Day
White, Nicholas J.
Arjen Dondorp
Francois Nosten
Nguyen, Thuy Nhien
Rupam Tripura
Peto, Tom J.
Lee, Sue J.
Lwin, Khin Maung
Preyanan Suangkanarat
Atthanee Jeeyapant
Benchawan Vihokhern
Klanarong Wongsaen
Hue, Dao Van
Dong, Le Thanh
Nguyen, Tam‑Uyen
Yoel Lubell
Seidlein, Lorenz von
Mehul Dhorda
Cholrawee Promnarate
Georges Snounou
Benoit Malleret
Laurent Rénia
Lilly Keereecharoen
Pratap Singhasivanon
Pasathorn Sirithiranont
Jem Chalk
Chea Nguon
Hien, Tran Tinh
Nicholas Day
White, Nicholas J.
Arjen Dondorp
Francois Nosten
Other Contributor(s)
Abstract
Background: The importance of the submicroscopic reservoir of Plasmodium infections for malaria elimination
depends on its size, which is generally considered small in low transmission settings. The precise estimation of this
reservoir requires more sensitive parasite detection methods. The prevalence of asymptomatic, sub-microscopic
malaria was assessed by a sensitive, high blood volume quantitative real-time polymerase chain reaction method in
three countries of the Greater Mekong Sub-region.
Methods: Cross-sectional surveys were conducted in three villages in western Cambodia, four villages along the
Thailand–Myanmar border and four villages in southwest Vietnam. Malaria parasitaemia was assessed by Plasmodium
falciparum/pan malaria rapid diagnostic tests (RDTs), microscopy and a high volume ultra-sensitive real-time polymerase
chain reaction (HVUSqPCR: limit of detection 22 parasites/mL). All villagers older than 6 months were invited to
participate.
Results: A census before the surveys identified 7355 residents in the study villages. Parasite prevalence was 224/5008
(4 %) by RDT, 229/5111 (5 %) by microscopy, and 988/4975 (20 %) when assessed by HVUSqPCR. Of these 164 (3 %)
were infected with P. falciparum, 357 (7 %) with Plasmodium vivax, 56 (1 %) with a mixed infection, and 411 (8 %) had
parasite densities that were too low for species identification. A history of fever, male sex, and age of 15 years or older
were independently associated with parasitaemia in a multivariate regression model stratified by site.
Conclusion: Light microscopy and RDTs identified only a quarter of all parasitaemic participants. The asymptomatic
Plasmodium reservoir is considerable, even in low transmission settings. Novel strategies are needed to eliminate this
previously under recognized reservoir of malaria transmission.