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Abstract：
BACKGROUND: The first dengue outbreak in Sao Tome and Principe was reported in 2022. Entomological investigations were undertaken to establish the typology of Aedes larval habitats, the distribution of Ae. aegypti and Ae. albopictus, the related entomological risk and the susceptibility profile of Ae. aegypti to insecticides, to provide evidence to inform the outbreak response.
RESULTS: Entomological surveys were performed in all seven health districts of Sao Tome and Principe during the dry and rainy seasons in 2022. WHO tube and synergist assays using piperonyl butoxide (PBO) and diethyl maleate (DEM) were carried out, together with genotyping of F1534C/V1016I/V410L mutations in Ae. aegypti. Aedes aegypti and Ae. albopictus were found in all seven health districts of the country with high abundance of Ae. aegypti in the most urbanised district, Agua Grande. Both Aedes species bred mainly in used tyres, discarded tanks and water storage containers. In both survey periods, the Breteau (BI > 50), house (HI > 35%) and container (CI > 20%) indices were higher than the thresholds established by WHO to indicate high potential risk of dengue transmission. The Ae. aegypti sampled were susceptible to all insecticides tested except dichlorodiphenyltrichloroethane (DDT) (9.2% mortality, resistant), bendiocarb (61.4% mortality, resistant) and alpha-cypermethrin (97% mortality, probable resistant). A full recovery was observed in Ae. aegypti resistant to bendiocarb after pre-exposure to synergist PBO. Only one Ae. aegypti specimen was found carrying F1534C mutation.
CONCLUSIONS: These findings revealed a high potential risk for dengue transmission throughout the year, with the bulk of larval breeding occurring in used tyres, water storage and discarded containers. Most of the insecticides tested remain effective to control Aedes vectors in Sao Tome, except DDT and bendiocarb. These data underline the importance of raising community awareness and implementing routine dengue vector control strategies to prevent further outbreaks in Sao Tome and Principe, and elsewhere in the subregion.
RESULTS: Entomological surveys were performed in all seven health districts of Sao Tome and Principe during the dry and rainy seasons in 2022. WHO tube and synergist assays using piperonyl butoxide (PBO) and diethyl maleate (DEM) were carried out, together with genotyping of F1534C/V1016I/V410L mutations in Ae. aegypti. Aedes aegypti and Ae. albopictus were found in all seven health districts of the country with high abundance of Ae. aegypti in the most urbanised district, Agua Grande. Both Aedes species bred mainly in used tyres, discarded tanks and water storage containers. In both survey periods, the Breteau (BI > 50), house (HI > 35%) and container (CI > 20%) indices were higher than the thresholds established by WHO to indicate high potential risk of dengue transmission. The Ae. aegypti sampled were susceptible to all insecticides tested except dichlorodiphenyltrichloroethane (DDT) (9.2% mortality, resistant), bendiocarb (61.4% mortality, resistant) and alpha-cypermethrin (97% mortality, probable resistant). A full recovery was observed in Ae. aegypti resistant to bendiocarb after pre-exposure to synergist PBO. Only one Ae. aegypti specimen was found carrying F1534C mutation.
CONCLUSIONS: These findings revealed a high potential risk for dengue transmission throughout the year, with the bulk of larval breeding occurring in used tyres, water storage and discarded containers. Most of the insecticides tested remain effective to control Aedes vectors in Sao Tome, except DDT and bendiocarb. These data underline the importance of raising community awareness and implementing routine dengue vector control strategies to prevent further outbreaks in Sao Tome and Principe, and elsewhere in the subregion.
摘要：
背景：圣多美和普林西比首次登革热暴发于2022年报告。进行了昆虫学调查，以建立伊蚊幼虫栖息地的类型，Ae的分布。埃及伊蚊和Ae.白纹,相关的昆虫学风险和Ae的易感性。埃及伊蚊杀虫剂，提供证据以告知疫情应对。
结果：在2022年的旱季和雨季期间，对圣多美和普林西比的所有七个卫生区进行了昆虫学调查。使用胡椒基丁醚（PBO）和马来酸二乙酯（DEM）进行了WHO试管和增效剂测定，以及Ae中F1534C/V1016I/V410L突变的基因分型。埃及伊蚊.埃及伊蚊和埃。在该国所有七个卫生区中都发现了白纹伊蚊，其Ae含量很高。埃及伊蚊在最城市化的地区，阿瓜·格兰德.两种伊蚊主要在旧轮胎中繁殖，废弃的水箱和储水容器。在这两个调查期间，Breteau（BI>50），房屋(HI>35%)和集装箱(CI>20%)指数高于世卫组织设定的提示登革热传播潜在风险较高的阈值.Ae.取样的埃及伊蚊对所有测试的杀虫剂都敏感，除了二氯二苯基三氯乙烷（DDT）（9.2%的死亡率，抗性)，bendiocarb（61.4%死亡率，抗性)和氯氰菊酯(97%死亡率，可能具有抗性）。在Ae中观察到完全恢复。在预暴露于增效剂PBO后，埃及伊蚊对苯迪威具有抗性。只有一个Ae。发现埃及伊蚊标本携带F1534C突变。
结论：这些发现揭示了全年登革热传播的高潜在风险，大部分幼虫繁殖发生在旧轮胎中，储水和废弃的容器。大多数测试的杀虫剂仍然有效控制圣多美的伊蚊媒介，除了滴滴涕和苯迪奥克.这些数据强调了提高社区意识和实施常规登革热媒介控制策略以防止圣多美和普林西比进一步爆发的重要性，以及该次区域的其他地方。
结果：在2022年的旱季和雨季期间，对圣多美和普林西比的所有七个卫生区进行了昆虫学调查。使用胡椒基丁醚（PBO）和马来酸二乙酯（DEM）进行了WHO试管和增效剂测定，以及Ae中F1534C/V1016I/V410L突变的基因分型。埃及伊蚊.埃及伊蚊和埃。在该国所有七个卫生区中都发现了白纹伊蚊，其Ae含量很高。埃及伊蚊在最城市化的地区，阿瓜·格兰德.两种伊蚊主要在旧轮胎中繁殖，废弃的水箱和储水容器。在这两个调查期间，Breteau（BI>50），房屋(HI>35%)和集装箱(CI>20%)指数高于世卫组织设定的提示登革热传播潜在风险较高的阈值.Ae.取样的埃及伊蚊对所有测试的杀虫剂都敏感，除了二氯二苯基三氯乙烷（DDT）（9.2%的死亡率，抗性)，bendiocarb（61.4%死亡率，抗性)和氯氰菊酯(97%死亡率，可能具有抗性）。在Ae中观察到完全恢复。在预暴露于增效剂PBO后，埃及伊蚊对苯迪威具有抗性。只有一个Ae。发现埃及伊蚊标本携带F1534C突变。
结论：这些发现揭示了全年登革热传播的高潜在风险，大部分幼虫繁殖发生在旧轮胎中，储水和废弃的容器。大多数测试的杀虫剂仍然有效控制圣多美的伊蚊媒介，除了滴滴涕和苯迪奥克.这些数据强调了提高社区意识和实施常规登革热媒介控制策略以防止圣多美和普林西比进一步爆发的重要性，以及该次区域的其他地方。
