Equine cutaneous gasterophilosis in an era of selective parasite control

For the first time this century, we report tract migration dermatitis provoked by Gasterophilus sp. larvae in horses at a farm in Spain where a selective parasite control programme has been employed for more than a decade. At this equine farm, two horses over 25 years old presented alopecic lesions in the form of streaks in the masseteric and maxillary region of the face. The clinical and histological features of these animals are described, with dermatological examination revealing the presence of nonoperculated eggs of Gasterophilus sp. when the lesions appeared. The morphology of the eggs corresponded to G. inermis and skin biopsy identified an eosinophilic superficial perivascular dermatitis. The horses were treated once with oral ivermectin, achieving complete resolution of the lesions.