A habitat suitability analysis for three Culicoides species implicated in bluetongue virus transmission in the Southeastern United States.

Culicoides biting midges adversely impact animal health through transmission of multiple orbiviruses, such as bluetongue virus (BTV). This study used light trapping data collected in the Southeastern United States for three Culicoides midge species that are confirmed or suspected BTV vectors: Culicoides insignis, Culicoides stellifer and Culicoides venustus. Midge presence datasets were combined with meteorological data and ecological data to model habitat suitability for each species. Logistic regression and machine learning models were used to generate individual species distribution models (SDMs). Results for each SDM method were combined in an ensemble model to create a distribution model for each midge species. Based on overlay analyses of livestock populations and midge suitable habitat, there is extensive overlap of cattle and goat populations and suitable habitat for C. insignis in Florida. Suitable habitat for C. stellifer intersects with cattle and goat populations in various counties in Alabama, Arkansas, the Carolinas, Florida, Georgia, Louisiana and Tennessee; and suitable habitat for C. venustus intersects with cattle and goat populations in the same states as C. stellifer, except for Florida. It is critical for orbivirus and midge surveillance to continue in the Southeastern United States as the habitat of all three midge species intersect with livestock populations.