Local investigation into the role of Culicoides species diversity (Diptera: Ceratopogonidae) in recurrent horse dermatitis cases in southwest France.

Background: Insect bite hypersensitivity in horses ("sweet itch") is a common pruritic, chronic, seasonal, and recurrent dermatitis affecting approximately 10% of horses in France and is a major concern for the horse industry and private owners. This dermatitis results from an allergic reaction to the saliva of specific biting flies (Diptera: Nematocera), primarily from the Culicoides genus. Given the frequent occurrence of this health problem and the limited investigation in France, we conducted a field survey in the vicinity of a riding stable in southwestern France with a reported chronic case of recurrent horse dermatitis to (i) characterize the Culicoides species associated with horse populations and (ii) estimate the relative abundance of the different species identified based on the trapping site location.