A new paradigm for Aedes spp. surveillance using gravid ovipositing sticky trap and NS1 antigen test kit

Sai Ming Lau,Indra Vythilingam,Balan Venugopalan,Wan-Yussof Sulaiman,Tock H Chua,Sylvia Joanne,Shamala Devi Sekaran,Karuthan Chinna,Yvonne Ai-Lian Lim

doi:10.1186/s13071-017-2091-y

Abstract

BackgroundDengue remains a serious public health problem in Southeast Asia and has increased 37-fold in Malaysia compared to decades ago. New strategies are urgently needed for early detection and control of dengue epidemics.MethodsWe conducted a two year study in a high human density dengue-endemic urban area in Selangor, where Gravid Ovipositing Sticky (GOS) traps were set up to capture adult Aedes spp. mosquitoes. All Aedes mosquitoes were tested using the NS1 dengue antigen test kit. All dengue cases from the study site notified to the State Health Department were recorded. Weekly microclimatic temperature, relative humidity (RH) and rainfall were monitored.ResultsAedes aegypti was the predominant mosquito (95.6%) caught in GOS traps and 23% (43/187 pools of 5 mosquitoes each) were found to be positive for dengue using the NS1 antigen kit. Confirmed cases of dengue were observed with a lag of one week after positive Ae. aegypti were detected. Aedes aegypti density as analysed by distributed lag non-linear models, will increase lag of 2–3 weeks for temperature increase from 28 to 30 °C; and lag of three weeks for increased rainfall.ConclusionProactive strategy is needed for dengue vector surveillance programme. One method would be to use the GOS trap which is simple to setup, cost effective (below USD 1 per trap) and environmental friendly (i.e. use recyclable plastic materials) to capture Ae. aegypti followed by a rapid method of detecting of dengue virus using the NS1 dengue antigen kit. Control measures should be initiated when positive mosquitoes are detected.

Highlights

Dengue remains a serious public health problem in Southeast Asia and has increased 37-fold in Malaysia compared to decades ago
In a previous study conducted in an urban area in peninsular Malaysia, we showed that the infected Ae. aegypti mosquito was obtained from sticky noninsecticidal traps before the first case was reported [53]
This study has shown that the use of Gravid Ovipositing Sticky (GOS) traps and NS1 kit represents one possible way forward to forewarn and reduce dengue outbreaks which are increasing yearly and projecting a global disease burden

Summary

Introduction

Dengue remains a serious public health problem in Southeast Asia and has increased 37-fold in Malaysia compared to decades ago. Dengue was first reported in Malaysia in the early 1900s [1]. It became endemic in the 1960s and has emerged as a major public health problem in Malaysia from 1973 [2, 3] to the new millennium [4]. The yearly rate of increase of reported cases rose from 47% between 2012–2013 to 62.1% between 2013–2014 [2012: 20,923 cases (35 deaths); 2013: 40,222 cases (92 deaths); 2014: 103,610 cases (215 deaths)] [15].

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