Classification of the main macroscopic lesions produced by larvae of Gasterophilus spp. (Diptera:Gasterophilidae) in free-ranging horses in Umbria.

Listed and described herein are the main macroscopic lesions produced along the whole digestive tract of free-ranging horses by larvae of the five Gasterophilus spp., occurring in Umbria, a region of central Italy: Gasterophilus intestinalis, Gasterophilus nasalis, Gasterophilus pecorum, Gasterophilus inermis, Gasterophilus haemorrhoidalis. Lesions are classified on the basis of their sizes and shapes and the host's anatomic sites infested, and they are examined in relation to the developmental stages of larvae causing them. The examination of the lesions shows that it is very difficult to differentiate the hemorrhagic impressions caused by migrating 1st and 2nd instar larvae of all the species in the absence of the specific parasite. It is also difficult to differentiate between the gastric lesions caused by Gasterophilus intestinalis and Gasterophilus pecorum. It has been found that an easy identification is possible even in the absence of parasites for gum lesions and for lesions on the soft palate produced respectively by Gasterophilus intestinalis and Gasterophilus pecorum, for duodenal lesions caused by Gasterophilus nasalis, for rectal lesions caused by Gasterophilus inermis and for duodenal and rectal lesions produced by Gasterophilus haemorrhoidalis.