Optimizing arbovirus surveillance using risk mapping and coverage modelling

Joni Downs,Mehrdad Vaziri,George Deskins,William Kellner,Kristi Miley,Thomas R Unnasch

doi:10.1080/19475683.2019.1688391

Joni Downs, Mehrdad Vaziri + Show 4 more

Open Access

https://doi.org/10.1080/19475683.2019.1688391

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Abstract

ABSTRACTDiseases carried by mosquitoes and other arthropods endanger human health globally. Though costly, surveillance efforts are vital for disease control and prevention This paper describes an approach for strategically configuring targeted disease surveillance sites across a study area. The methodology combines risk index mapping and spatial optimization modelling. The risk index is used to identify demand for surveillance, and the maximum covering location problem is used to select a specified number of candidate surveillance sites that covers the maximum amount of risk. The approach is demonstrated using a case study where optimal locations for sentinel surveillance sites are selected for the purposes of detecting eastern equine encephalitis virus in a county in the state of Florida. Optimal sentinel sites were selected under a number of scenarios that modelled different target populations (horses or humans), coverage distances (0.5, 1.0, and 1.5 km), and numbers of sites to select (1–12). Sentinel site selections for the horse and human models displayed different spatial patterns, with horse sites located largely in the west-central region and human ones in the north-central. Minor amounts of spatial overlap between the horse and human sites were observed, especially as coverage distances and numbers of sites were increased. Additionally, a near linear increase in risk coverage was observed as sites were incrementally added to the scenarios. This finding suggests that the number of sentinel sites within the ranges explored should be based on the maximum that can be funded, since they provide similar levels of benefit.

Highlights

Arboviruses – viruses transmitted by mosquitoes, flies, and arthropods – endanger human health globally (Gubler 2002)
This paper presents a methodology for strategically selecting targeted arbovirus surveillance sites under constraints of limited resources
This approach for selecting optimal sentinel surveillance sites initially relies upon risk index models to map equine encephalitis virus (EEEV) risk based on the composition and configuration of habitats associated with viral transmission

Summary

Introduction

Arboviruses – viruses transmitted by mosquitoes, flies, and arthropods – endanger human health globally (Gubler 2002). Popular methods of surveillance include the use of traps in combination with viral culture or molecular assays to detect the presence of the viruses of interest, the use of serological assays to detect exposure in sentinel animals, and standard epidemiological reporting techniques to collect data on the incidence of disease caused by viral infections They can be effective, these approaches are often labour intensive in both the field and laboratory, as well as financially expensive to implement. Recent studies suggest that Florida serves as a reservoir from which EEEV is periodically introduced to the rest of the eastern USA (Armstrong et al 2008), so it is an important region to monitor EEEV activity This approach for selecting optimal sentinel surveillance sites initially relies upon risk index models to map EEEV risk based on the composition and configuration of habitats associated with viral transmission. A discussion of the relative merits of each scenario is provided

Materials and methods

Results

Discussion and conclusions