Nextgen Vector Surveillance Tools: sensitive, specific, cost-effective and epidemiologically relevant

Robert Farlow,Thomas R Burkot,Tanya L Russell

doi:10.1186/s12936-020-03494-0

Robert Farlow, Thomas R Burkot + Show 1 more

Open Access

https://doi.org/10.1186/s12936-020-03494-0

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Abstract

BackgroundVector surveillance provides critical data for decision-making to ensure that malaria control programmes remain effective and responsive to any threats to a successful control and elimination programme. The quality and quantity of data collected is dependent on the sampling tools and laboratory techniques used which may lack the sensitivity required to collect relevant data for decision-making. Here, 40 vector control experts were interviewed to assess the benefits and limitations of the current vector surveillance tools and techniques. In addition, experts shared ideas on “blue sky” indicators which encompassed ideas for novel methods to monitor presently used indicators, or to measure novel vector behaviours not presently measured. Algorithms for deploying surveillance tools and priorities for understanding vector behaviours are also needed for collecting and interpreting vector data.ResultsThe available tools for sampling and analysing vectors are often hampered by high labour and resource requirements (human and supplies) coupled with high outlay and operating costs and variable tool performance across species and geographic regions. The next generation of surveillance tools needs to address the limitations of present tools by being more sensitive, specific and less costly to deploy to enable the collection and use of epidemiologically relevant vector data to facilitate more proactive vector control guidance. Ideas and attributes for Target Product Profiles (TPPs) generated from this analysis provide targets for research and funding to develop next generation tools.ConclusionsMore efficient surveillance tools and a more complete understanding of vector behaviours and populations will provide a basis for more cost effective and successful malaria control. Understanding the vectors’ behaviours will allow interventions to be deployed that target vulnerabilities in vector behaviours and thus enable more effective control. Through defining the strengths and weaknesses of the current vector surveillance methods, a foundation and initial framework was provided to define the TPPs for the next generation of vector surveillance methods. The draft TTPs presented here aim to ensure that the next generation tools and technologies are not encumbered by the limitations of present surveillance methods and can be readily deployed in low resource settings.

Highlights

Vector surveillance provides critical data for decision-making to ensure that malaria control programmes remain effective and responsive to any threats to a successful control and elimination programme
Vector surveillance will increasingly be critical to the success of national malaria control and elimination programmes in designing, planning and monitoring vector interventions as the number of World Health Organization (WHO) recommended vector control strategies
Farlow et al Malar J (2020) 19:432 increases beyond insecticide treated nets (ITNs), indoor residual spraying (IRS) and larval source management (LSM) [1, 2] The WHO considers surveillance, including vector surveillance, as a core intervention and recommends countries monitor specific malaria vector indicators according to the recommended control strategies implemented (e.g., Insecticide-treated nets (ITN), IRS or LSM) [3]

Summary

Introduction

Vector surveillance provides critical data for decision-making to ensure that malaria control programmes remain effective and responsive to any threats to a successful control and elimination programme. The primary objectives of vector surveillance, as outlined by the WHO, are to characterize receptivity (a function of vector presence and density to enable selection and stratification of interventions), to track malaria vector densities (for selection and timing of vector control deployment by biting time or seasonality of transmission), to monitor insecticide resistance (IR) for selecting insecticides for programme use, to identify other threats to vector control efficacy and to identify gaps in vector control intervention coverage [4] Monitoring these objectives requires tracking eight specific vector indicators (i.e., vector occurrence, vector density, blood feeding habits, indoor/outdoor biting, indoor/outdoor resting, insecticide resistance phenotypes, sporozoite infections and larval habitats) as well as indicators for monitoring intervention access and use. Forty vector control experts were interviewed to assess the frequency with which mosquito sampling techniques were used, the indicators that each technique had monitored, and the strengths and weaknesses of these established vector surveillance techniques

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