Predicting outbreaks: a spatial risk assessment of West Nile virus in British Columbia

Abstract

Background: West Nile virus (WNv) has recently emerged as a health threat to the North American population. After the initial disease outbreak in New York City in 1999, WNv has spread widely and quickly across North America to every contiguous American state and Canadian province, with the exceptions of British Columbia (BC), Prince Edward Island and Newfoundland. In this study we develop models of mosquito population dynamics for Culex tarsalis and C. pipiens, and create a spatial risk assessment of WNv prior to its arrival in BC by creating a raster-based mosquito abundance model using basic geographic and temperature data. Among the parameters included in the model are spatial factors determined from the locations of BC Centre for Disease Control mosquito traps (e.g., distance of the trap from the closest wetland or lake), while other parameters were obtained from the literature. Factors not considered in the current assessment but which could influence the results are also discussed.

Exploring the Spatio-Temporal Dynamics of Reservoir Hosts, Vectors, and Human Hosts of West Nile Virus: A Review of the Recent Literature

“…[48] applied raster-based approach to map Cx. tarsalis abundance and identified WNV risk prone areas in British Columbia.…”

“…Ecological studies of agent-vector-host relationships and improved surveillance methods have been cited as important priorities for addressing WNV epidemics, monitoring WNV spread, and predicting future outbreaks [45,46,47,48,49,50,51,52,53]. Ecological studies are also valuable because they may give insight into factors that affect temporal cycles in infectious disease risk [54,55].…”

“…For example, studies have attempted to model the distribution of infected pools of birds, horses, and mosquitoes. These studies are obviously limited by spatial biases where hosts are killed or died [45,46,47,48,56]. Local responses have utilized GIS technology, particularly in bird surveillance.…”

West Nile Virus State of the Art Report of MALWEST Project

“…From 1999 onwards, the virus spread to other states such as New Jersey, Connecticut, Massachusetts, and Maryland, forcing authorities to intensify their surveillance efforts by significantly developing GIS [161]. In a recent study in Canada, GIS, mosquito population data, climate data and land use were combined to identify areas of high probability of WNV dispersion [162]. In the state of Mississippi GIS in conjunction with data of birds positive to the virus, bioclimatic indices, vegetation and stream network used in the creation of many spatial models to identify and control the virus in spatial scale of municipalities and regions.…”

“…In a comprehensive study, Tachiiri et al [162] developed a sophisticated abundance model of Cx. tarsalis and Cx.…”