Department of Parasitology, Institute Aggeu Magalhães(IAM/FIOCRUZ Pernambuco), Recife, Brazil.
Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom.
PLoS Negl Trop Dis. 2018 Oct 16;12(10):e0006816. doi: 10.1371/journal.pntd.0006816. eCollection 2018 Oct.
Molecular xenomonitoring (MX)-pathogen detection in the mosquito rather than human-is a promising tool for lymphatic filariasis (LF) surveillance. In the Recife Metropolitan Region (RMR), the last LF focus in Brazil, Culex quinquefasciatus mosquitoes have been implicated in transmitting Wuchereria bancrofti parasites. This paper presents findings on the ideal mosquito collection method, mosquito dispersion, W. bancrofti infection in mosquitoes and W. bancrofti antigen in humans to aid MX development.
Experiments occurred within two densely populated urban areas of Olinda, RMR, in July and August 2015. U.S. Centers for Disease Control and Prevention (CDC) light traps were compared to battery-powered aspirators as collection methods, and mosquito dispersion was measured by mosquito mark release recapture (MMRR). Female Cx. quinquefasciatus were tested by PCR for W. bancrofti infection, and study area residents were screened by rapid tests for W. bancrofti antigen.
Aspirators caught 2.6 times more total Cx. quinquefasciatus, including 38 times more blood-fed and 5 times more gravid stages, than CDC light traps. They also collected 123 times more Aedes aegypti. Of the 9,644 marked mosquitoes released, only ten (0.01%) were recaptured, nine of which were < 50m (34.8m median, 85.4m maximum) from the release point. Of 9,169 unmarked mosquitoes captured in the MMR, 38.3% were unfed, 48.8% blood-fed, 5.5% semi-gravid, and 7.3% gravid. PCR on 182 pools (1,556 mosquitoes) found no evidence of W. bancrofti infection in Cx. quinquefasciatus. Rapid tests on 110 of 111 eligible residents were all negative for W. bancrofti antigen.
Aspirators were more effective than CDC light traps at capturing Ae. aegypti and all but unfed stages of Cx. quinquefasciatus. Female Cx. quinquefasciatus traveled short (< 86m) distances in this urban area. Lack of evidence for W. bancrofti infection in mosquitoes and antigen in humans in these fine-scale studies does not indicate that LF transmission has ceased in the RMR. A MX surveillance system should consider vector-specific collection methods, mosquito dispersion, and spatial scale but also local context, environmental factors such as sanitation, and host factors such as infection prevalence and treatment history.
分子 xenomonitoring（MX）-在蚊子中而非人类中检测病原体-是淋巴丝虫病（LF）监测的有前途的工具。在巴西最后一个 LF 焦点的累西腓大都市区（RMR），库蚊已被牵连传播班氏丝虫寄生虫。本文介绍了理想的蚊子收集方法、蚊子分散、蚊子中的 Wuchereria bancrofti 感染和人类中的 W. bancrofti 抗原，以帮助 MX 发展。
实验于 2015 年 7 月至 8 月在 RMR 的奥林达两个人口稠密的城区进行。美国疾病控制与预防中心（CDC）的光阱与电池驱动的吸气器进行了比较，作为收集方法，蚊子标记释放回收（MMRR）测量了蚊子的分散。用 PCR 检测雌性库蚊的 W. bancrofti 感染情况，用快速检测法筛查研究区居民的 W. bancrofti 抗原。
与 CDC 光阱相比，吸气器捕获的总库蚊数量多 2.6 倍，包括 38 倍的吸血和 5 倍的怀孕阶段。它们还捕获了 123 倍的埃及伊蚊。在释放的 9644 只标记蚊子中，只有 10 只（0.01%）被捕获，其中 9 只距离释放点<50m（中位 34.8m，最大 85.4m）。在 MMR 捕获的 9169 只未标记的蚊子中，38.3%未进食，48.8%吸血，5.5%半怀孕，7.3%怀孕。对 182 个（1556 只）蚊子的 PCR 检测未发现库蚊感染 W. bancrofti 的证据。对 111 名符合条件的居民中的 110 名进行的快速检测均为 W. bancrofti 抗原阴性。
与 CDC 光阱相比，吸气器在捕获埃及伊蚊和库蚊的所有除未吸血阶段外的阶段都更有效。在这个城市地区，雌性库蚊的活动范围较短（<86m）。在这些微观研究中，没有证据表明蚊子中存在 W. bancrofti 感染和人类中的抗原，这并不表明 RMR 中的 LF 传播已经停止。MX 监测系统应考虑特定于蚊子的收集方法、蚊子分散和空间尺度，但也要考虑当地情况、环境卫生因素（如卫生）和宿主因素（如感染率和治疗史）。
