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

Research

Klanarong Wongsaen¹  Dao Van Hue²  Pratap Singhasivanon³  Le Thanh Dong⁴  Rupam Tripura⁵  Tom J. Peto⁵  Atthanee Jeeyapant⁵  Pasathorn Sirithiranont⁵  Preyanan Suangkanarat⁵  Jem Chalk⁵  Yoel Lubell⁵  Nicholas J. White⁶  Lorenz von Seidlein⁶  Arjen Dondorp⁶  Sue J. Lee⁶  Nicholas Day⁶  Mallika Imwong⁷  Francois Nosten⁸  Chea Nguon⁹  Thuy Nhien Nguyen^1,10  Tam-Uyen Nguyen^1,10  Tran Tinh Hien^1,11  Benchawan Vihokhern^1,12  Khin Maung Lwin^1,12  Lilly Keereecharoen^1,12  Laurent Rénia^1,13  Benoit Malleret^1,14  Georges Snounou^1,15  Mehul Dhorda^1,16  Cholrawee Promnarate^1,16 

[1] Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand;Center for Malariology, Parasitology and Entomology Control, Phan Rang-Thap Cham, Ninh Thuan Province, Vietnam;Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Institute of Malariology-Parasitology, Entomology (IMPE) of Ho Chi Minh City, 699 Tran Hung Dao Q5, Ho Chi Minh City, Vietnam;Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK;Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Tak, Thailand;Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK;National Center for Parasitology, Entomology and Malaria Control, No. 372, Preah Monivong, 12302, Phnom Penh, Cambodia;Oxford University Clinical Research Unit, Hospital for Tropical Diseases, 764 Vo Van Kiet, District 5, Ho Chi Minh City, Vietnam;Oxford University Clinical Research Unit, Hospital for Tropical Diseases, 764 Vo Van Kiet, District 5, Ho Chi Minh City, Vietnam;Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Churchill Hospital, Oxford, UK;Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Tak, Thailand;Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, 278177, Singapore, Singapore;Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, 278177, Singapore, Singapore;Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, 5 Science Drive 2, Blk MD4, Level 3, 117597, Singapore, Singapore;Sorbonne Universités, UPMC Univ Paris 06, UPMC UMRS CR7, 75005, Paris, France;Centre d’Immunologie et de Maladies Infectieuses (CIMI), Paris, Institut National de la Santé et de la Recherche Médicale (Inserm) U1135, Centre National de la Recherche Scientifique (CNRS) ERL 8255, 75013, Paris, France;WWARN Asia Regional Centre, Mahidol University, Bangkok, Thailand;

关键词: Malaria;    P. falciparum;    P. vivax;    Sub-microscopic;    Epidemiology;    South-East Asia;    Myanmar;    Thailand;    Cambodia;    Vietnam;    Greater Mekong Sub-region;   

DOI  :  10.1186/s12936-015-0906-x

 received in 2015-07-10, accepted in 2015-09-05,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundThe 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.MethodsCross-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.ResultsA 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.ConclusionLight 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.

【 授权许可】

CC BY   
© Imwong et al. 2015