The Useful Life of Bed-nets for Malaria Control in Tanzania: Attrition, Bio-efficacy, Chemistry, Durability and Insecticide Resistance, 2016

Long-Lasting Insecticidal Nets (LLINs) are the current first line choice in malaria vector control in sub-Saharan Africa (SSA), with most countries adopting universal coverage campaigns with free or subsidised nets. However, there is only limited knowledge from few countries of the effective life of LLINs under user conditions, an essential parameter for determining the operational and cost-effectiveness of this strategy. This study investigated LLIN effectiveness by measuring attrition, bio-efficacy, chemical content and physical degradation in Tanzania. A two-stage approach was used: Firstly, LLINs from recent net campaigns was evaluated retrospectively. The sampled households was then be provided with one of three leading LLIN products and followed up for three years in a prospective study to compare the performance of the LLIN brands in vivo. There was also developed a GIS-based network to understand potential spatial reasons for net loss and deterioration; to monitor insecticide resistance and to show malaria incidence data collected from local health centres and national surveys. A highly skilled multi-disciplinary team was brought together that supported the Tanzanian vector control both then and in the future through the training of two Tanzanian PhD students. This was the first team to conduct a geographically representative study of LLIN use and efficacy using WHO-recommended methodologies and large sample sizes determined by robust statistical methods with independent data quality assurance. The data collected will be of importance to policy makers and vector control specialists in both Tanzania and the SSA region to inform best practice for the maintenance of high and cost-effective coverage to maximize current gains in malaria control. This study consists of two data collections, this part contains 8 datasets.长效杀虫蚊帐（Long-Lasting Insecticidal Nets, LLINs）是目前撒哈拉以南非洲（sub-Saharan Africa, SSA）疟疾媒介防控的一线首选方案，多数国家通过免费或补贴蚊帐的方式推行全民覆盖行动。然而目前仅有少数国家掌握了用户实际使用场景下LLINs的有效使用寿命数据，而该参数是评估该防控策略运营效益与成本效益的核心必要指标。本研究通过在坦桑尼亚境内测量蚊帐的损耗率、生物效能、化学药剂含量与物理降解情况，对LLINs的实际有效性展开系统性调查。 本研究采用两阶段研究设计：第一阶段，对近期疟疾防控蚊帐发放行动中使用的LLINs进行回顾性评估；第二阶段，为抽样家庭配发三款主流LLIN产品中的一款，并开展为期三年的前瞻性随访研究，以对比不同品牌LLINs在实际使用场景下的性能。此外，本研究还搭建了基于地理信息系统（Geographic Information System, GIS）的分析网络平台，用于解析蚊帐流失与老化的潜在空间影响因素、监测杀虫剂抗性水平，并展示从当地卫生中心与全国调查中获取的疟疾发病数据。 研究团队集结了一支高水准的多学科队伍，通过培养2名坦桑尼亚籍博士生，为坦桑尼亚当前及未来的疟疾媒介防控工作提供持续支持。本研究是首个采用世界卫生组织（World Health Organization, WHO）推荐方法学、基于稳健统计方法确定大样本量并配备独立数据质量保障机制的地理代表性LLINs使用与效能研究。 本研究采集的相关数据将为坦桑尼亚及撒哈拉以南非洲地区的政策制定者与媒介防控专家提供重要参考依据，助力优化维持高成本效益覆盖水平的最佳实践，以最大化当前疟疾防控工作已取得的成果。 本研究包含两批次数据采集工作，本部分共包含8个数据集。