{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,7]],"date-time":"2026-04-07T17:04:35Z","timestamp":1775581475635,"version":"3.50.1"},"reference-count":28,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T00:00:00Z","timestamp":1631836800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T00:00:00Z","timestamp":1631836800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/100009896","name":"U.S. Navy","doi-asserted-by":"publisher","award":["D1430"],"award-info":[{"award-number":["D1430"]}],"id":[{"id":"10.13039\/100009896","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000865","name":"Bill and Melinda Gates Foundation","doi-asserted-by":"publisher","award":["OPP1193472_2018"],"award-info":[{"award-number":["OPP1193472_2018"]}],"id":[{"id":"10.13039\/100000865","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004440","name":"Wellcome Trust","doi-asserted-by":"publisher","award":["106698\/Z\/14\/Z"],"award-info":[{"award-number":["106698\/Z\/14\/Z"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Malar J"],"published-print":{"date-parts":[[2021,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec>\n                <jats:title>Background<\/jats:title>\n                <jats:p>A key step to advancing the goal of malaria elimination in Viet Nam by 2030 is focusing limited resources for treatment and prevention to groups most at risk for malaria transmission.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Methods<\/jats:title>\n                <jats:p>To better understand risk factors for malaria transmission in central Viet Nam, a survey of 1000 malaria positive cases and 1000 malaria negative controls was conducted. Cases and controls were matched for age and gender and self-presented at commune health stations (CHS) in Binh Phuoc, Dak Nong and Dak Lak Provinces. Diagnoses were confirmed with microscopy, rapid diagnostic test and PCR. Participants were interviewed about 50 potential risk factors for malaria, which included information about occupation, forest visitation, travel, healthcare-seeking behaviour and prior use of anti-malaria interventions. Participants were enrolled by trained government health workers and the samples were analysed in Vietnamese government laboratories. Data were analysed by univariable, block-wise and multivariable logistic regression.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>Among cases, 61.8% had <jats:italic>Plasmodium falciparum<\/jats:italic>, 35.2% <jats:italic>Plasmodium vivax<\/jats:italic> and 3% mixed species infections. Median (IQR) age was 27 (21\u201336) years and 91.2% were male. Twenty-five risk factors were associated with being a case and eleven with being a control. Multivariable analysis found that malaria cases correlated with forest workers, recent forest visitation, longer duration of illness, having a recorded fever, number of malaria infections in the past year, having had prior malaria treatment and having previously visited a clinic.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusions<\/jats:title>\n                <jats:p>This study demonstrates the benefits of increased statistical power from matched controls in malaria surveillance studies, which allows identification of additional independent risk factors. It also illustrates an example of research partnership between academia and government to collect high quality data relevant to planning malaria elimination activities. Modifiable risk factors and implications of the findings for malaria elimination strategy are presented.<\/jats:p>\n              <\/jats:sec>","DOI":"10.1186\/s12936-021-03908-7","type":"journal-article","created":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T10:03:29Z","timestamp":1631873009000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Risk factors for malaria in high incidence areas of Viet Nam: a case\u2013control study"],"prefix":"10.1186","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5355-0562","authenticated-orcid":false,"given":"Richard J.","family":"Maude","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thang Duc","family":"Ngo","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Duong Thanh","family":"Tran","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Binh Thi Huong","family":"Nguyen","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dung Viet","family":"Dang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Long Khanh","family":"Tran","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Gregory","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rapeephan R.","family":"Maude","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ipsita","family":"Sinha","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kulchada","family":"Pongsoipetch","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicholas J.","family":"Martin","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2021,9,17]]},"reference":[{"key":"3908_CR1","unstructured":"Government Socialist Republic of Vietnam. National strategy for malaria control and elimination in the period 2011\u20132020 and orientation to 2030. 2011."},{"key":"3908_CR2","volume-title":"World Malaria Report","author":"WHO","year":"2018","unstructured":"WHO. World Malaria Report. Geneva: World Health Organization; 2018."},{"key":"3908_CR3","volume-title":"World Malaria Report","author":"WHO","year":"2019","unstructured":"WHO. World Malaria Report. Geneva: World Health Organization; 2019."},{"key":"3908_CR4","volume-title":"National Malaria Programme Review - Viet Nam","author":"WHO Western Pacific Region","year":"2018","unstructured":"WHO Western Pacific Region. National Malaria Programme Review - Viet Nam. Manila: World Health Organization; 2018."},{"key":"3908_CR5","volume-title":"Mekong malaria elimination epidemiology summary","author":"WHO","year":"2019","unstructured":"WHO. Mekong malaria elimination epidemiology summary. Phnom Penh: World Health Organization; 2019."},{"key":"3908_CR6","doi-asserted-by":"publisher","first-page":"414","DOI":"10.1186\/s12936-017-2060-0","volume":"16","author":"I Chen","year":"2017","unstructured":"Chen I, Thanh HNT, Lover A, Thao PT, Luu TV, Thang HN, et al. Malaria risk factors and care-seeking behaviour within the private sector among high-risk populations in Vietnam: a qualitative study. Malar J. 2017;16:414.","journal-title":"Malar J"},{"key":"3908_CR7","doi-asserted-by":"publisher","first-page":"e76316","DOI":"10.1371\/journal.pone.0076316","volume":"8","author":"R Wampfler","year":"2013","unstructured":"Wampfler R, Mwingira F, Javati S, Robinson L, Betuela I, Siba P, et al. Strategies for detection of Plasmodium species gametocytes. PLoS ONE. 2013;8:e76316.","journal-title":"PLoS ONE."},{"key":"3908_CR8","doi-asserted-by":"publisher","first-page":"393","DOI":"10.1186\/1475-2875-13-393","volume":"13","author":"TM Tran","year":"2014","unstructured":"Tran TM, Aghili A, Li S, Ongoiba A, Kayentao K, Doumbo S, et al. A nested real-time PCR assay for the quantification of Plasmodium falciparum DNA extracted from dried blood spots. Malar J. 2014;13:393.","journal-title":"Malar J"},{"key":"3908_CR9","volume-title":"Policy brief on single-dose primaquine as a gametocytocide in Plasmodium falciparum malaria","author":"WHO","year":"2015","unstructured":"WHO. Policy brief on single-dose primaquine as a gametocytocide in Plasmodium falciparum malaria. Geneva: World Health Organization; 2015."},{"key":"3908_CR10","doi-asserted-by":"publisher","first-page":"110","DOI":"10.4269\/ajtmh.2004.70.110","volume":"70","author":"A Erhart","year":"2004","unstructured":"Erhart A, Thang ND, Hung NQ, le Toi V, le Hung X, Tuy TQ, et al. Forest malaria in Vietnam: a challenge for control. Am J Trop Med Hyg. 2004;70:110\u20138.","journal-title":"Am J Trop Med Hyg"},{"key":"3908_CR11","doi-asserted-by":"publisher","first-page":"435","DOI":"10.1186\/s12936-019-3068-4","volume":"18","author":"SE Canavati","year":"2019","unstructured":"Canavati SE, Kelly GC, Quintero CE, Vo TH, Tran LK, Ohrt C, et al. Risk factor assessment for clinical malaria among forest-goers in a pre-elimination setting in Phu Yen Province. Vietnam Malar J. 2019;18:435.","journal-title":"Vietnam Malar J"},{"key":"3908_CR12","doi-asserted-by":"publisher","first-page":"56","DOI":"10.1186\/s12936-017-1703-5","volume":"16","author":"R Tripura","year":"2017","unstructured":"Tripura R, Peto TJ, Veugen CC, Nguon C, Davoeung C, James N, et al. Submicroscopic Plasmodium prevalence in relation to malaria incidence in 20 villages in western Cambodia. Malar J. 2017;16:56.","journal-title":"Malar J"},{"key":"3908_CR13","doi-asserted-by":"publisher","first-page":"e1002745","DOI":"10.1371\/journal.pmed.1002745","volume":"16","author":"L von Seidlein","year":"2019","unstructured":"von Seidlein L, Peto TJ, Landier J, Nguyen TN, Tripura R, Phommasone K, et al. The impact of targeted malaria elimination with mass drug administrations on falciparum malaria in Southeast Asia: a cluster randomised trial. PLoS Med. 2019;16:e1002745.","journal-title":"PLoS Med."},{"key":"3908_CR14","doi-asserted-by":"publisher","first-page":"512","DOI":"10.1186\/s13071-017-2407-y","volume":"10","author":"W Nguitragool","year":"2017","unstructured":"Nguitragool W, Mueller I, Kumpitak C, Saeseu T, Bantuchai S, Yorsaeng R, et al. Very high carriage of gametocytes in asymptomatic low-density Plasmodium falciparum and P. vivax infections in western Thailand. Parasit Vectors. 2017;10:512.","journal-title":"Parasit Vectors"},{"key":"3908_CR15","doi-asserted-by":"publisher","first-page":"240","DOI":"10.1186\/s12936-019-2871-2","volume":"18","author":"CEG Mercado","year":"2019","unstructured":"Mercado CEG, Lawpoolsri S, Sudathip P, Kaewkungwal J, Khamsiriwatchara A, Pan-Ngum W, et al. Spatiotemporal epidemiology, environmental correlates, and demography of malaria in Tak Province, Thailand (2012\u20132015). Malar J. 2019;18:240.","journal-title":"Malar J"},{"key":"3908_CR16","doi-asserted-by":"publisher","first-page":"455","DOI":"10.1016\/j.ijpara.2019.01.004","volume":"49","author":"W Nguitragool","year":"2019","unstructured":"Nguitragool W, Karl S, White M, Koepfli C, Felger I, Singhasivanon P, et al. Highly heterogeneous residual malaria risk in western Thailand. Int J Parasitol. 2019;49:455\u201362.","journal-title":"Int J Parasitol"},{"key":"3908_CR17","doi-asserted-by":"publisher","first-page":"32","DOI":"10.1186\/s40537-018-0143-6","volume":"5","author":"G Smith","year":"2018","unstructured":"Smith G. Step away from stepwise. J Big Data. 2018;5:32.","journal-title":"J Big Data"},{"key":"3908_CR18","doi-asserted-by":"publisher","first-page":"845","DOI":"10.4269\/ajtmh.1937.s1-17.845","volume":"1","author":"MF Boyd","year":"1937","unstructured":"Boyd MF, Kitchen SF. The duration of the intrinsic incubation period in falciparum malaria in relation to certain factors affecting the parasites. Am J Trop Med Hyg. 1937;1:845\u20138.","journal-title":"Am J Trop Med Hyg"},{"key":"3908_CR19","doi-asserted-by":"publisher","first-page":"184","DOI":"10.3947\/ic.2013.45.2.184","volume":"45","author":"SJ Kim","year":"2013","unstructured":"Kim SJ, Kim SH, Jo SN, Gwack J, Youn SK, Jang JY. The long and short incubation periods of Plasmodium vivax malaria in Korea: the characteristics and relating factors. Infect Chemother. 2013;45:184\u201393.","journal-title":"Infect Chemother"},{"key":"3908_CR20","doi-asserted-by":"publisher","first-page":"109","DOI":"10.1016\/j.ijpara.2010.08.005","volume":"41","author":"HM Bui","year":"2011","unstructured":"Bui HM, Clements AC, Nguyen QT, Nguyen MH, Le XH, Hay SI, et al. Social and environmental determinants of malaria in space and time in Viet Nam. Int J Parasitol. 2011;41:109\u201316.","journal-title":"Int J Parasitol"},{"key":"3908_CR21","doi-asserted-by":"publisher","first-page":"454","DOI":"10.1186\/s13071-019-3695-1","volume":"12","author":"HM Edwards","year":"2019","unstructured":"Edwards HM, Chinh VD, Le Duy B, Thanh PV, Thang ND, Trang DM, et al. Characterising residual malaria transmission in forested areas with low coverage of core vector control in central Viet Nam. Parasit Vectors. 2019;12:454.","journal-title":"Parasit Vectors"},{"key":"3908_CR22","doi-asserted-by":"publisher","first-page":"e29991","DOI":"10.1371\/journal.pone.0029991","volume":"7","author":"KP Grietens","year":"2012","unstructured":"Grietens KP, Xuan XN, Ribera J, Duc TN, Bortel W, Ba NT, et al. Social determinants of long lasting insecticidal hammock use among the Ra-glai ethnic minority in Vietnam: implications for forest malaria control. PLoS One. 2012;7:e29991.","journal-title":"PLoS One."},{"key":"3908_CR23","unstructured":"President\u2019s Malaria Initiative. Thailand, Lao PDR and Regional Abbreviated Malaria Operational Plan FY 2019. 2019. https:\/\/www.pmi.gov\/docs\/default-source\/default-document-library\/malaria-operational-plans\/fy19\/fy-2019-thailand-abbreviated-malaria-operational-plan.pdf?sfvrsn=5, Accessed 1 Apr 2021."},{"key":"3908_CR24","doi-asserted-by":"publisher","first-page":"919","DOI":"10.1111\/j.1365-3156.2005.01472.x","volume":"10","author":"PT Giao","year":"2005","unstructured":"Giao PT, Vries PJ, Binh TQ, Nam NV, Kager PA. Early diagnosis and treatment of uncomplicated malaria and patterns of health seeking in Vietnam. Trop Med Int Health. 2005;10:919\u201325.","journal-title":"Trop Med Int Health"},{"key":"3908_CR25","volume-title":"Guidelines for the treatment of malaria","author":"WHO","year":"2015","unstructured":"WHO. Guidelines for the treatment of malaria. Geneva: World Health Organization; 2015."},{"key":"3908_CR26","doi-asserted-by":"publisher","first-page":"86","DOI":"10.1186\/s12936-015-0601-y","volume":"14","author":"PV Thanh","year":"2015","unstructured":"Thanh PV, Van Hong N, Van Van N, Van Malderen C, Obsomer V, Rosanas-Urgell A, et al. Epidemiology of forest malaria in Central Vietnam: the hidden parasite reservoir. Malar J. 2015;14:86.","journal-title":"Malar J"},{"key":"3908_CR27","doi-asserted-by":"publisher","first-page":"45","DOI":"10.1186\/s12916-020-1512-5","volume":"18","author":"I Sinha","year":"2020","unstructured":"Sinha I, Sayeed AA, Uddin D, Wesolowski A, Zaman SI, Faiz MA, et al. Mapping the travel patterns of people with malaria in Bangladesh. BMC Med. 2020;18:45.","journal-title":"BMC Med"},{"key":"3908_CR28","doi-asserted-by":"publisher","first-page":"26","DOI":"10.4103\/2224-3151.255346","volume":"8","author":"M Inkochasan","year":"2019","unstructured":"Inkochasan M, Gopinath D, Vicario E, Lee A, Duigan P. Access to health care for migrants in the Greater Mekong Subregion: policies and legal frameworks and their impact on malaria control in the context of malaria elimination. WHO South East Asia J Public Health. 2019;8:26\u201334.","journal-title":"WHO South East Asia J Public Health"}],"container-title":["Malaria Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s12936-021-03908-7.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1186\/s12936-021-03908-7\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s12936-021-03908-7.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T10:13:12Z","timestamp":1631873592000},"score":1,"resource":{"primary":{"URL":"https:\/\/malariajournal.biomedcentral.com\/articles\/10.1186\/s12936-021-03908-7"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,9,17]]},"references-count":28,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2021,12]]}},"alternative-id":["3908"],"URL":"https:\/\/doi.org\/10.1186\/s12936-021-03908-7","relation":{},"ISSN":["1475-2875"],"issn-type":[{"value":"1475-2875","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,9,17]]},"assertion":[{"value":"23 April 2021","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"7 September 2021","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"17 September 2021","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"This study was approved by the Viet Nam Ministry of Health Ethics Committee and reviewed by the U.S. Department of the Navy Human Research Protection Program in compliance with all applicable federal regulations governing the protection of human subjects (HRPO.NMRCA.2018.0004 and HRPO.NMRCA.2018.0010). All participants provided written, informed consent to participate.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The authors declare that they have no competing interests.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"373"}}