Ministerio de Salud de Panamá (MINSA), Panama City, República de Panamá.
Malaria Elimination Initiative (MEI), University of California, San Francisco (UCSF), USA.
Malar J. 2021 Nov 24;20(1):443. doi: 10.1186/s12936-021-03972-z.
Though most of Panamá is free from malaria, localized foci of transmission persist, including in the Guna Yala region. Government-led entomological surveillance using an entomological surveillance planning tool (ESPT) sought to answer programmatically-relevant questions that would enhance the understanding of both local entomological drivers of transmission and gaps in protection that result in persisting malaria transmission to guide local vector control decision-making.
The ESPT was used to design a sampling plan centered around the collection of minimum essential indicators to investigate the relevance of LLINs and IRS in the communities of Permé and Puerto Obaldía, Guna Yala, as well as to pinpoint any remaining spaces and times where humans are exposed to Anopheles bites (gaps in protection). Adult Anopheles were collected at three time points via human landing catches (HLCs), CDC Light Traps (LT), and pyrethrum spray catches (PSCs) during the rainy and dry seasons. Mosquitoes were identified to species via molecular methods. Insecticide susceptibility testing of the main vector species to fenitrothion was conducted.
In total, 7537 adult Anopheles were collected from both sites. Of the 493 specimens molecularly confirmed to species, two thirds (n = 340) were identified as Nyssorhynchus albimanus, followed by Anopheles aquasalis. Overall Anopheles human biting rates (HBRs) were higher outdoors than indoors, and were higher in Permé than in Puerto Obaldía: nightly outdoor HBR ranged from 2.71 bites per person per night (bpn) (Puerto Obaldía), to 221.00 bpn (Permé), whereas indoor nightly HBR ranged from 0.70 bpn (Puerto Obaldía) to 81.90 bpn (Permé). Generally, peak biting occurred during the early evening. The CDC LT trap yields were significantly lower than that of HLCs and this collection method was dropped after the first collection. Pyrethrum spray catches resulted in only three indoor resting Anopheles collected. Insecticide resistance (IR) of Ny. albimanus to fenitrothion was confirmed, with only 65.5% mortality at the diagnostic time.
The early evening exophagic behaviour of Anopheles vectors, the absence of indoor resting behaviours, and the presence of resistance to the primary intervention insecticide demonstrate limitations of the current malaria strategy, including indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs), and point to both gaps in protection and to the drivers of persisting malaria transmission in Guna Yala. These findings highlight the need for continued and directed entomological surveillance, based on programmatic questions, that generates entomological evidence to inform an adaptive malaria elimination strategy.
尽管巴拿马大部分地区没有疟疾，但仍存在局部传播焦点，包括在瓜纳雅拉地区。政府主导的使用昆虫学监测规划工具（ESPT）进行的昆虫学监测旨在回答具有计划相关性的问题，这些问题将增强对当地传播媒介驱动因素和导致持续疟疾传播的保护空白的理解，以指导当地的病媒控制决策。
使用 ESPT 设计了一个采样计划，该计划围绕收集最低必要指标进行，以调查 Permé 和 Puerto Obaldía 社区中 LLIN 和 IRS 的相关性，以及确定任何仍然存在的人类暴露于疟蚊叮咬的时间和地点（保护空白）。在雨季和旱季，通过人类降落捕捉（HLC）、CDC 灯诱（LT）和除虫菊喷雾捕捉（PSC），在三个时间点收集成年疟蚊。通过分子方法对蚊子进行物种鉴定。对主要媒介物种进行了对三硫磷的杀虫剂敏感性测试。
总共从两个地点采集了 7537 只成年疟蚊。在通过分子方法确认的 493 个标本中，三分之二（n=340）被鉴定为 Nyssorhynchus albimanus，其次是 Anopheles aquasalis。总体而言，户外的疟蚊人血指数（HBR）高于室内，Permé 的 HBR 高于 Puerto Obaldía：夜间户外 HBR 范围从每晚每人为 2.71 个（Puerto Obaldía）到 221.00 个（Permé），而夜间室内 HBR 范围从每晚 0.70 个（Puerto Obaldía）到 81.90 个（Permé）。通常，叮咬高峰发生在傍晚。CDC LT 诱捕器的产量明显低于 HLC，并且在第一次收集后就放弃了这种收集方法。除虫菊喷雾捕获仅收集到三只室内休息的疟蚊。证实了 N. albimanus 对三硫磷的抗药性，仅在诊断时间有 65.5%的死亡率。
疟蚊传播媒介的傍晚外食行为、室内休息行为的缺乏以及对主要干预性杀虫剂的抗药性，表明当前疟疾策略存在局限性，包括室内滞留喷洒（IRS）和长效杀虫剂处理蚊帐（LLIN），并指出了瓜纳雅拉持续疟疾传播的保护空白和驱动因素。这些发现强调了需要根据计划问题继续进行和指导基于虫媒监测，以产生虫媒学证据，为适应性疟疾消除策略提供信息。
