在塞内加尔东南部大规模投服伊维菌素会降低野外捕获、吸食血液的疟疾传播媒介的存活率。
Mass drug administration of ivermectin in south-eastern Senegal reduces the survivorship of wild-caught, blood fed malaria vectors.
机构信息
Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology & Pathology, Colorado State University, Fort Collins, Colorado, USA.
出版信息
Malar J. 2010 Dec 20;9:365. doi: 10.1186/1475-2875-9-365.
BACKGROUND
In south-eastern Senegal, malaria and onchocerciasis are co-endemic. Onchocerciasis in this region has been controlled by once or twice yearly mass drug administration (MDA) with ivermectin (IVM) for over fifteen years. Since laboratory-raised Anopheles gambiae s.s. are susceptible to ivermectin at concentrations found in human blood post-ingestion of IVM, it is plausible that a similar effect could be quantified in the field, and that IVM might have benefits as a malaria control tool.
METHODS
In 2008 and 2009, wild-caught blood fed An. gambiae s.l. mosquitoes were collected from huts of three pairs of Senegalese villages before and after IVM MDAs. Mosquitoes were held in an insectary to assess their survival rate, subsequently identified to species, and their blood meals were identified. Differences in mosquito survival were statistically analysed using a Glimmix model. Lastly, changes in the daily probability of mosquito survivorship surrounding IVM MDAs were calculated, and these data were inserted into a previously developed, mosquito age-structured model of malaria transmission.
RESULTS
Anopheles gambiae s.s. (P < 0.0001) and Anopheles arabiensis (P = 0.0191) from the treated villages had significantly reduced survival compared to those from control villages. Furthermore, An gambiae s.s. caught 1-6 days after MDA in treated villages had significantly reduced survival compared to control village collections (P = 0.0003), as well as those caught pre-MDA (P < 0.0001) and >7 days post-MDA (P < 0.0001). The daily probability of mosquito survival dropped >10% for the six days following MDA. The mosquito age-structured model of malaria transmission demonstrated that a single IVM MDA would reduce malaria transmission (Ro) below baseline for at least eleven days, and that repeated IVM MDAs would result in a sustained reduction in malaria Ro.
CONCLUSIONS
Ivermectin MDA significantly reduced the survivorship of An. gambiae s.s. for six days past the date of the MDA, which is sufficient to temporarily reduce malaria transmission. Repeated IVM MDAs could be a novel and integrative malaria control tool in areas with seasonal transmission, and which would have simultaneous impacts on neglected tropical diseases in the same villages.
背景
在塞内加尔东南部，疟疾和盘尾丝虫病呈共流行状态。该地区的盘尾丝虫病已通过每年一到两次用伊维菌素（IVM）进行大规模药物治疗（MDA）得到控制，这一措施已实施了超过十五年。由于实验室饲养的冈比亚按蚊对伊维菌素的敏感性与人类摄入伊维菌素后血液中的浓度相当，因此在野外环境中也可能会出现类似的效果，并且伊维菌素可能作为一种疟疾控制工具带来益处。
方法
在 2008 年和 2009 年，在伊维菌素 MDA 前后，从塞内加尔三个村庄的三对小屋中收集了野外捕获的吸食了人血的冈比亚按蚊。将蚊子放在昆虫饲养室中以评估其存活率，随后对其进行鉴定，并确定其血液来源。使用 Glimmix 模型对蚊子存活率的差异进行了统计学分析。最后，计算了伊维菌素 MDA 前后蚊子每日存活概率的变化，并将这些数据插入到之前开发的、基于蚊子年龄结构的疟疾传播模型中。
结果
与对照村庄相比，来自治疗村庄的冈比亚按蚊（斯氏）（P < 0.0001）和冈比亚按蚊（阿拉伯亚种）（P = 0.0191）的存活率显著降低。此外，与对照村庄相比，在治疗村庄 MDA 后 1-6 天捕获的冈比亚按蚊（斯氏）的存活率显著降低（P = 0.0003），与 MDA 前（P < 0.0001）和 MDA 后 >7 天（P < 0.0001）的相比，其存活率也显著降低。MDA 后六天内，蚊子每日存活概率下降了>10%。疟疾传播的蚊子年龄结构模型表明，单次伊维菌素 MDA 将使疟疾传播率（Ro）在基线以下至少持续 11 天，并且重复进行伊维菌素 MDA 将导致疟疾 Ro 的持续降低。
结论
伊维菌素 MDA 显著降低了冈比亚按蚊（斯氏）在 MDA 日期后六天的存活率，这足以暂时降低疟疾传播率。在季节性传播地区，重复进行伊维菌素 MDA 可能成为一种新颖的、综合的疟疾控制工具，并且在同一村庄中也会对被忽视的热带病产生影响。
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