de Jesus Camila P, Dias Fernando B S, Villela Daniel M A, Maciel-de-Freitas Rafael
Laboratório de Mosquitos Transmissores de Hematozoários, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro-RJ 21040-360, Brazil.
Gabinete da Presidência, Fiocruz, Rio de Janeiro 21040-361, Brazil.
Insects. 2020 Feb 1;11(2):92. doi: 10.3390/insects11020092.
Deployment of Aedes aegypti mosquitoes carrying the endosymbiont bacterium has been identified as a promising strategy to reduce dengue, chikungunya, and Zika transmission. We investigated whether sampling larvae from ovitraps can provide reliable estimates on frequency during releases, as compared to the expensive adult-based BG-Sentinel. We conducted pilot releases in a semi-field system (SFS) divided into six cages of 21 m, each with five ovitraps. Five treatments were chosen to represent different points of a hypothetical invasion curve: 10%, 25%, 50%, 75%, and 90% of frequency. Collected eggs were counted and hatched, and the individuals from a net sample of 27% of larvae per treatment were screened for presence by RT-qPCR. Ovitrap positioning had no effect on egg hatching rate. Treatment strongly affected the number of eggs collected and also the hatching rate, especially when was at a 10% frequency. A second observation was done during the release of in Rio under a population replacement approach when bacterium frequency was estimated using 30 BG-Sentinel traps and 45 ovitraps simultaneously. By individually screening 35% (N = 3904) of larvae collected by RT-qPCR, we were able to produce a similar invasion curve to the one observed when all adults were individually screened. If sampling is reduced to 20%, monitoring frequency with 45 ovitraps would be roughly half the cost of screening all adult mosquitoes captured by 30 BG-Sentinels. Our findings support the scale-up of releases, especially in areas with limited resources to afford massive trapping with BG-Sentinel traps.
释放携带内共生菌的埃及伊蚊已被确定为减少登革热、基孔肯雅热和寨卡病毒传播的一种有前景的策略。我们调查了与昂贵的基于成虫的BG-Sentinel诱捕器相比，从诱蚊产卵器中采集幼虫样本是否能在释放期间提供关于频率的可靠估计。我们在一个半野外系统（SFS）中进行了试点释放，该系统分为六个21米的笼子，每个笼子有五个诱蚊产卵器。选择了五种处理方式来代表假设入侵曲线的不同点：频率的10%、25%、50%、75%和90%。对收集到的卵进行计数并孵化，通过RT-qPCR对每个处理中27%的幼虫净样本中的个体进行频率筛查。诱蚊产卵器的位置对卵的孵化率没有影响。处理方式强烈影响了收集到的卵的数量以及孵化率，尤其是当频率为10%时。在里约热内卢采用种群替代方法释放期间进行了第二次观察，当时同时使用30个BG-Sentinel诱捕器和45个诱蚊产卵器估计细菌频率。通过对RT-qPCR收集的35%（N = 3904）的幼虫进行单独筛查，我们能够得出与对所有成虫进行单独筛查时观察到的类似入侵曲线。如果将采样率降低到20%，使用45个诱蚊产卵器监测频率的成本大约是筛查30个BG-Sentinel诱捕器捕获的所有成年蚊子成本的一半。我们的研究结果支持扩大释放规模，特别是在资源有限、无法负担使用BG-Sentinel诱捕器进行大规模诱捕的地区。
