Combining Mosquito Vector and Human Disease Data for Improved Assessment of Spatial West Nile Virus Disease Risk

Abstract

Assessments of spatial risk of exposure to vector-borne pathogens that combine vector and human disease data are needed for areas encompassing large tracts of public land with low population bases. We addressed this need for West Nile virus (WNV) disease in the northern Colorado Front Range by developing not only a spatial model for entomological risk of exposure to Culex tarsalis WNV vectors and an epidemiological risk map for WNV disease but also a novel risk-classification index combining data for these independently derived measures of entomological and epidemiological risk. Risk of vector exposure was high in the densely populated eastern plains portion of the Front Range but low in cooler montane areas to the west that are sparsely populated but used heavily for recreation in the summer. The entomological risk model performed well when applied to the western, mountainous part of Colorado and validated against epidemiologic data.

Spatial Risk Assessments Based on Vector-Borne Disease Epidemiologic Data: Importance of Scale for West Nile Virus Disease in Colorado

“…There is no question that sub-county variability exists for risk of exposure to mosquito and tick vectors of human pathogens such as WNV and the Lyme disease spirochete, Borrelia burgdorferi , in the United States. [28][29][30][31][32] The basic problem when working with sub-county spatial risk patterns developed based on epidemiologic data is to determine which of the resulting patterns are real and which are likely to be analysis artifacts. Such artifacts may occur for several reasons including that 1) case files for common vector-borne diseases, such as WNV disease and Lyme disease, often lack information for likely site of vector and pathogen exposure and thus the address of residence may not be the exposure location; Privacy issues associated with dissemination of information for disease case locations (can be addressed by random offsets from actual case locations).…”

Mosquitoes and West Nile Virus Along a River Corridor from Prairie to Montane Habitats in Eastern Colorado

“…This is now being complemented by studies on mosquito distribution and abundance patterns, mosquito blood-feeding behavior, and enzootic WNV transmission in a wider range of ecological settings including the prairie landscape of the plains (current study; Janousek andKramer 1999, Kent et al 2009) and foothills and montane habitats at the eastern edge of the Rocky Mountains , Winters et al 2008.…”

“…tarsalis and Cx. pipiens are abundant in the plains landscape at the foot of the Rocky Mountains but that their abundance decreases dramatically as one moves into montane habitats at higher elevations , Winters et al 2008). We also recorded dramatic changes in mosquito species richness, composition, and abundance along elevation gradients (1,500-2,400 m) in western Larimer County .…”

Zoonotic Infections Among Employees from Great Smoky Mountains and Rocky Mountain National Parks, 2008–2009

“…These ecosystems include a variety of native wildlife and associated arthropods which may carry pathogens that cause zoonotic infections from direct animal or vector-borne contact (Rayor 1985;McLean et al 1989;New et al 1993;Taylor et al 1997;Gese et al 1997;Mills et al 1998;Rhyan et al 2001;Riley et al 2004;Reeves 2007;Greger 2007;Winters et al 2008).…”