Ghinai Isaac, Cook Jackie, Hla Teddy Tun Win, Htet Hein Myat Thu, Hall Tom, Lubis Inke Nd, Ghinai Rosanna, Hesketh Therese, Naung Ye, Lwin Mya Mya, Latt Tint Swe, Heymann David L, Sutherland Colin J, Drakeley Chris, Field Nigel
Research Department of Infection and Population Health, University College London, London, WC1E 6JB, UK.
Malaria Centre, London School of Hygiene and Tropical Medicine, London, UK.
Malar J. 2017 Jan 5;16(1):16. doi: 10.1186/s12936-016-1651-5.
The spread of artemisinin-resistant Plasmodium falciparum is a global health concern. Myanmar stands at the frontier of artemisinin-resistant P. falciparum. Myanmar also has the highest reported malaria burden in Southeast Asia; it is integral in the World Health Organization's plan to eliminate malaria in Southeast Asia, yet few epidemiological data exist for the general population in Myanmar.
This cross-sectional, probability household survey was conducted in Phyu township, Bago Region (central Myanmar), during the wet season of 2013. Interviewers collected clinical and behavioural data, recorded tympanic temperature and obtained dried blood spots for malaria PCR and serology. Plasmodium falciparum positive samples were tested for genetic mutations in the K13 region that may confer artemisinin resistance. Estimated type-specific malaria PCR prevalence and seroprevalence were calculated, with regression analysis to identify risk factors for seropositivity to P. falciparum. Data were weighted to account for unequal selection probabilities.
1638 participants were sampled (500 households). Weighted PCR prevalence was low (n = 41, 2.5%) and most cases were afebrile (93%). Plasmodium falciparum was the most common species (n = 19. 1.1%) and five (26%) P. falciparum samples harboured K13 mutations. Plasmodium knowlesi was detected in 1.0% (n = 16) and Plasmodium vivax was detected in 0.4% (n = 7). Seroprevalence was 9.4% for P. falciparum and 3.1% for P. vivax. Seroconversion to P. falciparum was 0.003/year in the whole population, but 16-fold higher in men over 23 years old (LR test p = 0.016).
This is the first population-based seroprevalence study from central Myanmar. Low overall prevalence was discovered. However, these data suggest endemic transmission continues, probably associated with behavioural risk factors amongst working-age men. Genetic mutations associated with P. falciparum artemisinin resistance, the presence of P. knowlesi and discrete demographic risk groups present opportunities and challenges for malaria control. Responses targeted to working-age men, capable of detecting sub-clinical infections, and considering all species will facilitate malaria elimination in this setting.
耐青蒿素恶性疟原虫的传播是一个全球卫生问题。缅甸处于耐青蒿素恶性疟原虫传播的前沿。缅甸也是东南亚报告疟疾负担最高的国家；它是世界卫生组织东南亚疟疾消除计划的重要组成部分，但缅甸普通人群的流行病学数据很少。
2013年雨季期间，在勃固省彪镇（缅甸中部）进行了这项横断面概率家庭调查。访员收集临床和行为数据，记录鼓膜温度，并采集干血斑用于疟疾PCR检测和血清学检测。对恶性疟原虫阳性样本进行K13区域基因突变检测，这些突变可能导致青蒿素耐药性。计算估计的特定类型疟疾PCR患病率和血清阳性率，并进行回归分析以确定恶性疟原虫血清阳性的危险因素。对数据进行加权以考虑不等的选择概率。
共抽取1638名参与者（500户家庭）。加权PCR患病率较低（n = 41，2.5%），大多数病例无发热症状（93%）。恶性疟原虫是最常见的种类（n = 19，1.1%），5份（26%）恶性疟原虫样本存在K13突变。诺氏疟原虫检出率为1.0%（n = 16），间日疟原虫检出率为0.4%（n = 7）。恶性疟原虫血清阳性率为9.4%，间日疟原虫血清阳性率为3.1%。整个人群中恶性疟原虫血清转化率为0.003/年，但23岁以上男性的血清转化率高16倍（似然比检验p = 0.016）。
这是缅甸中部首次基于人群的血清阳性率研究。发现总体患病率较低。然而，这些数据表明地方性传播仍在继续，可能与劳动年龄男性的行为危险因素有关。与恶性疟原虫青蒿素耐药性相关的基因突变、诺氏疟原虫的存在以及不同的人口统计学风险群体给疟疾控制带来了机遇和挑战。针对劳动年龄男性、能够检测亚临床感染并考虑所有疟原虫种类的应对措施将有助于在这种情况下消除疟疾。
