A network analysis framework to improve the delivery of mosquito abatement services in Machala, Ecuador

Catherine A Lippi,Jason K Blackburn,Naveed Heydari,Anna M Stewart-Ibarra,Efraín Beltrán Ayala,Liang Mao,Sadie J Ryan,Nathan D Burkett-Cadena

doi:10.1186/s12942-020-0196-6

Abstract

BackgroundVector-borne disease places a high health and economic burden in the American tropics. Comprehensive vector control programs remain the primary method of containing local outbreaks. With limited resources, many vector control operations struggle to serve all affected communities within their districts. In the coastal city of Machala, Ecuador, vector control services, such as application of larvicides and truck-mounted fogging, are delivered through two deployment facilities managed by the Ecuadorian Ministry of Health. Public health professionals in Machala face several logistical issues when delivering mosquito abatement services, namely applying limited resources in ways that will most effectively suppress vectors of malaria, dengue, and encephalitis viruses.MethodsUsing a transportation network analysis framework, we built models of service areas and optimized delivery routes based on distance costs associated with accessing neighborhoods throughout the city. Optimized routes were used to estimate the relative cost of accessing neighborhoods for mosquito control services in Machala, creating a visual tool to guide decision makers and maximize mosquito control program efficiency. Location-allocation analyses were performed to evaluate efficiency gains of moving service deployment to other available locations with respect to distance to service hub, neighborhood population, dengue incidence, and housing condition.ResultsUsing this framework, we identified different locations for targeting mosquito control efforts, dependent upon management goals and specified risk factors of interest, including human population, housing condition, and reported dengue incidence. Our models indicate that neighborhoods on the periphery of Machala with the poorest housing conditions are the most costly to access. Optimal locations of facilities for deployment of control services change depending on pre-determined management priorities, increasing the population served via inexpensive routes up to 34.9%, and reducing overall cost of accessing neighborhoods up to 12.7%.ConclusionsOur transportation network models indicate that current locations of mosquito control facilities in Machala are not ideal for minimizing driving distances or maximizing populations served. Services may be optimized by moving vector control operations to other existing public health facilities in Machala. This work represents a first step in creating a spatial tool for planning and critically evaluating the systematic delivery of mosquito control services in Machala and elsewhere.

Highlights

Vector-borne disease places a high health and economic burden in the American tropics
Establishment of service areas Given the centralized location of the two active mosquito abatement deployment facilities in Machala, estimated catchment areas of service based on driving distance from facilities radiate from the city’s center, indicating greater impedance to access of peripheral neighborhoods, in particular the Puerto Bolivar port region in the west (Fig. 3)
The distance-based approaches used in this study, including formation of service areas, optimization of service routes, and exploration of goal-oriented management strategies, have not been previously used in this capacity and can serve as a template for locations in other countries burdened with mosquito-borne disease transmission

Summary

Introduction

Vector-borne disease places a high health and economic burden in the American tropics. Comprehensive vector control programs are widely acknowledged as a fiscally conservative strategy for suppressing and preventing outbreaks of mosquito-borne diseases in Latin America, employing combinations of surveillance, abatement, and educational outreach to the public [5,6,7,8,9]. The costs incurred by vector control efforts can still pose a significant burden, in communities with limited funds dedicated to public health activities [10]. This is relevant in Latin America, but throughout the world where vector control measures are a major component of vector-borne disease management for dengue, malaria, and more. Spatial optimization of vector control program planning and resource allocation is pertinent anywhere where vectored diseases are problematic, ranging from local to regional scales

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