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. 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. Among cases, 61.8% had Plasmodium falciparum, 35.2% Plasmodium vivax and 3% mixed species infections. Median (IQR) age was 27 (21–36) 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. 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.

中文翻译：

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越南高发地区疟疾的危险因素：病例对照研究

推进到 2030 年越南消除疟疾目标的关键步骤是将有限的资源集中用于治疗和预防疟疾传播风险最高的人群。为了更好地了解越南中部疟疾传播的风险因素，对 1000 名疟疾阳性病例和 1000 名疟疾阴性对照进行了调查。病例和对照的年龄和性别相匹配，并在平福省、多农省和多乐省的社区卫生站 (CHS) 自我介绍。诊断通过显微镜检查、快速诊断测试和 PCR 得到证实。参与者接受了大约 50 个疟疾潜在风险因素的访谈，其中包括有关职业、森林探访、旅行、寻求医疗保健的行为和先前使用抗疟疾干预措施的信息。参与者由训练有素的政府卫生工作者招募，样本在越南政府实验室进行分析。通过单变量、分块和多变量逻辑回归分析数据。在病例中，61.8% 有恶性疟原虫、35.2% 间日疟原虫和 3% 混合种感染。中位 (IQR) 年龄为 27 (21-36) 岁，91.2% 为男性。25 个风险因素与病例相关，11 个风险因素与对照相关。多变量分析发现，疟疾病例与森林工人、最近到过森林、病程较长、发烧记录、过去一年中感染疟疾的次数、以前接受过疟疾治疗和以前去过诊所有关。这项研究证明了疟疾监测研究中匹配对照增加统计功效的好处，这可以识别额外的独立风险因素。它还举例说明了学术界和政府之间的研究合作伙伴关系，以收集与规划消除疟疾活动相关的高质量数据。介绍了可修改的风险因素和调查结果对消除疟疾战略的影响。