Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Malar J. 2010 May 26;9:143. doi: 10.1186/1475-2875-9-143.
The probability of contracting malaria in a given individual is determined not only by the individual's characteristics, but also the ecological factors that characterize the level of human-vector contact in the population. Examination of the relationship between "individual" and "supra-individual" variables over time is important for understanding the local malaria epidemiology. This is essential for planning effective intervention strategies specifically for each location.
A retrospective cohort study was conducted, which followed a community-cohort of about 3,500 residents in seven hamlets along the Thai-Myanmar border between 1999 and 2006. Potential malaria determinants measured at different levels (temporal variables, individual variables, and hamlet variables) were incorporated into multilevel models to estimate their effects on an individual's risk of malaria attack.
The monthly minimum temperature was significantly associated with the seasonal variation of malaria risk. An individual risk of malaria attack decreased by about 50% during the period that active surveillance was conducted; an additional 15% and 25% reduction of Plasmodium falciparum and Plasmodium vivax incidence, respectively, was observed after the use of artesunate-mefloquine combination therapy (ACT) for treatment of P. falciparum. Male children (age < 16 years old) were at highest risk of both P. falciparum and P. vivax attack. An increase in the hamlet's incidence of P. falciparum and P. vivax by 1 per 100 persons in a previous month resulted in 1.14 and 1.34 times increase in the risk of P. falciparum and P. vivax, respectively, among individuals in a particular hamlet.
In a small area with low malaria transmission intensity, the variation in mosquito abundance is relatively similar across the residential areas; incidence of malaria between hamlets, which reflects the community level of human infectious reservoirs, is an important predictor for the malaria risk among individuals within these hamlets. Therefore, local malaria control strategies should focus on interventions that aim to reduce the gametocyte carriage in the population, such as early detection and treatment programmes and the use of ACT for P. falciparum.
个体感染疟疾的概率不仅取决于个体特征，还取决于反映人群中人与媒介接触水平的生态因素。随着时间的推移，检查“个体”和“超个体”变量之间的关系对于了解当地疟疾流行病学非常重要。这对于针对每个地点制定有效的干预策略至关重要。
进行了一项回顾性队列研究，该研究跟踪了 1999 年至 2006 年间泰缅边境七个小村庄约 3500 名居民的社区队列。在不同层面（时间变量、个体变量和村庄变量）测量的潜在疟疾决定因素被纳入多水平模型，以估计它们对个体疟疾发作风险的影响。
月最低温度与疟疾风险的季节性变化显著相关。在积极监测期间，个体疟疾发作的风险降低了约 50%；在使用青蒿琥酯-甲氟喹联合疗法（ACT）治疗恶性疟原虫后，分别观察到恶性疟原虫和间日疟原虫发病率降低了 15%和 25%。16 岁以下的男童患恶性疟原虫和间日疟原虫的风险最高。前一个月村庄恶性疟原虫和间日疟原虫发病率每增加 100 人，个体在特定村庄的恶性疟原虫和间日疟原虫风险分别增加 1.14 倍和 1.34 倍。
在疟疾传播强度较低的小区域，蚊媒数量的变化在居住区域内相对相似；村庄间疟疾的发病率反映了人群中人类感染源的社区水平，是个体在这些村庄内疟疾风险的重要预测指标。因此，当地疟疾控制策略应侧重于旨在减少人群中配子体携带的干预措施，例如早期发现和治疗计划以及使用 ACT 治疗恶性疟原虫。
