Comparative evaluation of anopheline sampling methods in three localities in Indonesia

Brandyce St Laurent,Sumardi Sumardi,Shinta Shinta,Amalia Safitri,Puji B Asih,Neil F Lobo,William A Hawley,David Bretz,Supratman Sukowati,Syah Firman,Suwito Suwito,Timothy A Burton,Mulyadi Zio,Thomas R Burkot,Frank H Collins,Sully Kosasih,Heru Sudibyo,Din Syafruddin

doi:10.1186/s12936-017-2161-9

Abstract

BackgroundThe effectiveness of vector control efforts can vary based on the interventions used and local mosquito behaviour and adaptability. In many settings, biting patterns of Anopheles mosquitoes can shift in response to interventions targeting indoor-biting mosquitoes, often resulting in higher proportions of mosquitoes feeding outside or at times when people are not protected. These behaviourally resistant mosquitoes have been shown to sustain residual malaria transmission and limit control efforts. Therefore, it is important to accurately sample mosquitoes to understand their behaviour.MethodsA variety of traps were evaluated in three geographically diverse sites in malaria-endemic Indonesia to investigate local mosquito feeding behaviour and determine effective traps for surveillance.ResultsEight traps were evaluated in three sites: Canti village, Lampung, Kaliharjo village, Purworejo, and Saketa village, Halmahera, Indonesia, including the gold standard human landing collection (HLC) and a variety of traps targeting host-seeking and resting mosquitoes both indoors and outdoors. Trapping, using indoor and outdoor HLC, the Ifakara tent trap C, goat and human-occupied tents, resting pots and boxes, and CDC miniature light traps was conducted for 16 nights in two sites and 8 nights in a third site, using a Latin square design. Trap efficacy varied by site, with outdoor HLC yielding the highest catch rates in Canti and Kaliharjo and a goat-baited tent trap proving most effective in Saketa. In Canti village, anthropophilic Anopheles sundaicus were caught indoors and outdoors using HLCs, peaking in the early morning. In Kaliharjo, a variety of mosquitoes were caught, mostly outdoors throughout the night. HLC was ineffective in Saketa, the only site where a goat-baited tent trap was tested. This trap was effective in catching zoophilic vectors outdoors before midnight.ConclusionsDifferent trapping methods were suitable for different species, likely reflecting differences in behaviour among species. The three villages, each located on a different island in the Indonesian archipelago, contained mosquito populations with unique behaviours. These data suggest that the effectiveness of specific vector monitoring and control measures may vary by location.

Highlights

The effectiveness of vector control efforts can vary based on the interventions used and local mosquito behaviour and adaptability
The purpose of this study is to evaluate the best anopheline sampling methods in various transmission settings within Indonesia for continued mosquito collections, and to characterize resident primary and secondary vectors that may exhibit various bionomic traits
In Kaliharjo village, Purworejo, 286 total anophelines were collected over 16 nights; they were morphologically identified as An. aconitus (n = 228), An. balabacensis (n = 46), Anopheles barbirostris (n = 11), and Anopheles vagus (n = 1) (Table 2)

Summary

Introduction

The effectiveness of vector control efforts can vary based on the interventions used and local mosquito behaviour and adaptability. In many settings, biting patterns of Anopheles mosquitoes can shift in response to interventions targeting indoor-biting mosquitoes, often resulting in higher proportions of mosquitoes feeding outside or at times when people are not protected. These behaviourally resistant mosquitoes have been shown to sustain residual malaria transmission and limit control efforts. The choice of sampling method is largely influenced by local species-specific behaviour and the entomological endpoint of interest (e.g., indoor/outdoor biting rates, biting times, bloodfeeding preference, and resting locations of blood-fed mosquitoes) [15, 16]. It is important to evaluate mosquito sampling methods in various malaria-endemic regions with inter-regional vector diversity that may arise from differing climates, human activity patterns, seasonality, or other inherent ecological or entomological differences

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