Cutaneous macroscopic and microscopic lesions caused by Pennella sp., Crassicauda sp. and Phyllobothrium delphini in Cetaceans

Recently skin changes have been considered valuableindicators of health in free-ranging cetaceans and severalstudies have been performed worldwide using photo-ID.The aim of the study was to describe the macroscopicparasitic lesions and their less-known correlated micro-scopic patterns. In this study skin samples collected from67 cetaceans (35 Stenella coeruleoalba,20Tursiops trun-catus,4Grampus griseus,4Balaenoptera physalus,3Physeter macrocephalus and 1 Ziphius cavirostris), foundstranded along the Italian coastline in the period 2011–2015, were examined macro- and microscopically. Para-sitic cutaneous lesions were reported in 29 animals: Pen-nella sp. (18), Phyllobothrium delphini (9) and Crassicaudasp. (5). Pennella sp. was visible at external examination,while histological lesions revealed epidermal, dermal andsubcutaneous focal necrosis associated with an intenseneutrophilic infiltrate, sometimes involving the underlyingmuscle. Phyllobothrium delphini appeared macroscopi-cally as round cysts in the blubber or abdominal muscula-ture. Histologically the larvae were lined by a fibrouscapsule with a thin internal rim of scant inflammatorycells. Crassicauda sp. was found as roundworms in thefascia between the deep blubber and the subcutaneousmuscle. Microscopically there was a mild infiltrate aroundthe parasite or around the fistula. In conclusion, our studydescribed the macroscopic and microscopic aspects ofseveral parasitic cutaneous lesions, which should be partof a systematic observation of skin lesions in live animalsand part of routine sampling in dead animals.