Entomological Surveillance Planning Tool (ESPT)-generated actionable evidence on human and vector behaviours optimizes present interventions and reduces exposure to Anopheles vectors in two communities of Guna Yala, Panama

BackgroundAlthough most of Panama 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 on local entomological drivers of transmission and gaps in protection to guide local vector control decision-making.MethodsThe ESPT was used to design a sampling plan to answer priority programmatic questions about the appropriateness of Long Lasting Insecticidal Nets (LLINs) and spaces and times where humans remain exposed to Anopheles bites (gaps in protection) in the communities of Perme and Puerto Obaldia, Guna Yala. Adult Anopheles were sampled at three time points via human landing catches (HLCs) during the rainy and dry seasons (2018/2019). Human behaviour observations (HBOs) were conducted alongside HLCs to examine intervention use, indoor versus outdoor activity, and sleeping patterns. HLC and HBO data were integrated to evaluate HBO-adjusted human biting rate (HBR).ResultsA total of 7,431 adult Anopheles were collected across both sites. Of the 450 specimens molecularly confirmed to species-level, 75.5% (n = 340) were confirmed as Anopheles Nyssorhynchus albimanus, followed by Anopheles (Ny.) aquasalis. Anopheles host seeking activity was demonstrated to be primarily exophagic throughout all sampling periods and in both communities. When adjusted with HBOs, exposure to mosquito bites was predominantly indoors and overnight in Perme (Nov, Mar), compared to predominantly outdoors in Puerto Obaldia (Nov, Mar, Jul). Differences in site-specific human-vector exposure profiles were due to contrasting cultural and lifestyle practices between Perme and Puerto Obaldia (possibly partly influenced by the absence of electricity in Perme), and lower LLIN use in Perme. This evidence supported a previously planned LLIN campaign alongside a social behaviour change communication (SBCC) strategy in the Guna Yala Comarca (Jul 2019), which increased LLIN use. In turn, this led to a reduction of indoor exposure to mosquito bites, and a shift to predominant outdoor exposure to mosquito bites.ConclusionESPT-based question-driven planning and the integration of HBOs, intervention, and HLC data generated evidence towards answering the programmatic questions. This evidence enabled the characterization of site-specific human-vector exposure profiles, and the quantification of remaining gaps in protection. These data also provide important insights into remaining gaps in protection that must be addressed to further reduce human exposure to mosquito bites at these sites.

Automated summary

This study used an Entomological Surveillance Planning Tool (ESPT) to investigate malaria transmission in the Guna Yala region of Panama. The results showed that there are localized foci of transmission and identified gaps in protection. The data from human behavior observations and mosquito sampling were integrated to guide local vector control decision-making.