Mapping the distribution of Culicoides sonorensis (Diptera: Ceratopogonidae) in southern Alberta (Canada) and Montana (U.S.A.)

Bluetongue (BT) and Epizootic Hemorrhagic Disease (EHD) are diseases of ungulates caused by closely related viruses of the genus Orbivirus. The main arthropod vector for BT and EHD in western North America is considered to be Culicoides sonorensis. Outbreaks of EHDV and BTV commonly occur in the south-western United States, but have also been reported in Montana and less commonly cases in south-western Canada. The purpose of this study is to develop a distribution map for Culicoides sonorensis using vector species occurrence and environmental and climate data. Biting midge trapping was conducted in eight locations (years 2002-2003-2004), one location (years 2005-2006), four locations (year 2009) and ten locations (year 2010) in Southern Alberta and in thirty-one (2002) and nineteen (2003) locations in Montana. Culicoides spp. were collected using blacklight traps. Remotely sensed variables (Land Cover, Normalised Difference Vegetation Index, day-time and night-time Land Surface Temperature and Vapour Pressure Deficit), and Digital Elevation Models attributes were obtained and derived. The species distribution model was then generated using GIS points where Culicoides sonorensis was detected and environmental layers using a maximum entropy algorithm (MaxEnt software package 3.3.3e) which has been shown to be robust in modelling species distribution from presence-only data. The results will be used to generate Culicoides sonorensis risk map that will be used to develop a targeted Bluetongue surveillance system in the region.