Abad-Franch Fernando, Zamora-Perea Elvira, Ferraz Gonçalo, Padilla-Torres Samael D, Luz Sérgio L B
Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane-Fiocruz Amazônia, Manaus, Brazil.
Departamento de Ecologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Biological Dynamics of Forest Fragments Project, Smithsonian Tropical Research Institute/Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil.
PLoS Negl Trop Dis. 2015 Apr 7;9(4):e0003702. doi: 10.1371/journal.pntd.0003702. eCollection 2015 Apr.
Mosquito-borne pathogens pose major public health challenges worldwide. With vaccines or effective drugs still unavailable for most such pathogens, disease prevention heavily relies on vector control. To date, however, mosquito control has proven difficult, with low breeding-site coverage during control campaigns identified as a major drawback. A novel tactic exploits the egg-laying behavior of mosquitoes to have them disseminate tiny particles of a potent larvicide, pyriproxyfen (PPF), from resting to breeding sites, thus improving coverage. This approach has yielded promising results at small spatial scales, but its wider applicability remains unclear.
METHODOLOGY/PRINCIPAL FINDINGS: We conducted a four-month trial within a 20-month study to investigate mosquito-driven dissemination of PPF dust-particles from 100 'dissemination stations' (DSs) deployed in a 7-ha sub-area to surveillance dwellings and sentinel breeding sites (SBSs) distributed over an urban neighborhood of about 50 ha. We assessed the impact of the trial by measuring juvenile mosquito mortality and adult mosquito emergence in each SBS-month. Using data from 1,075 dwelling-months, 2,988 SBS-months, and 29,922 individual mosquitoes, we show that mosquito-disseminated PPF yielded high coverage of dwellings (up to 100%) and SBSs (up to 94.3%). Juvenile mosquito mortality in SBSs (about 4% at baseline) increased by over one order of magnitude during PPF dissemination (about 75%). This led to a >10-fold decrease of adult mosquito emergence from SBSs, from approximately 1,000-3,000 adults/month before to about 100 adults/month during PPF dissemination.
CONCLUSIONS/SIGNIFICANCE: By expanding breeding-site coverage and boosting juvenile mosquito mortality, a strategy based on mosquito-disseminated PPF has potential to substantially enhance mosquito control. Sharp declines in adult mosquito emergence can lower vector/host ratios, reducing the risk of disease outbreaks. This approach is a very promising complement to current and novel mosquito control strategies; it will probably be especially relevant for the control of urban disease vectors, such as Aedes and Culex species, that often cause large epidemics.
蚊媒病原体给全球公共卫生带来了重大挑战。由于针对大多数此类病原体的疫苗或有效药物仍然无法获得，疾病预防严重依赖于病媒控制。然而，迄今为止，蚊虫控制已被证明很困难，控制活动期间繁殖地覆盖率低被认为是一个主要缺点。一种新策略利用蚊子的产卵行为，使它们将一种强效杀幼虫剂——吡丙醚（PPF）的微小颗粒从栖息地点传播到繁殖地点，从而提高覆盖率。这种方法在小空间尺度上已产生了有希望的结果，但其更广泛的适用性仍不明确。
方法/主要发现：在一项为期20个月的研究中，我们进行了为期四个月的试验，以调查从部署在一个7公顷子区域内的100个“传播站”（DS）向分布在一个约50公顷城市社区的监测住宅和哨兵繁殖地点（SBS）传播PPF粉尘颗粒的情况。我们通过测量每个SBS月的幼蚊死亡率和成年蚊羽化率来评估试验的影响。利用来自1075个住宅月、2988个SBS月和29922只个体蚊子的数据，我们表明，由蚊子传播的PPF实现了对住宅（高达100%）和SBS（高达94.3%）的高覆盖率。在PPF传播期间，SBS中的幼蚊死亡率（基线时约为4%）增加了一个多数量级（约75%）。这导致SBS中成年蚊羽化率下降了10倍以上，从之前的每月约1000 - 3000只成年蚊降至PPF传播期间的每月约100只成年蚊。
结论/意义：通过扩大繁殖地覆盖率和提高幼蚊死亡率，基于蚊子传播PPF的策略有可能大幅加强蚊虫控制。成年蚊羽化率的急剧下降可降低病媒/宿主比率，减少疾病爆发的风险。这种方法是对当前和新型蚊虫控制策略非常有前景的补充；它可能对控制城市病媒，如经常引发大规模疫情的伊蚊和库蚊属物种特别重要。
