Retrospective study of nematodes infestation associated pathology of the urinary tract in short-finned pilot whales stranded in the Canary Islands (2013-2018)

Abstract

This retrospective study is focused on the pathology associated with the infestation and obstruction by nematodes (Crassicauda spp) of the genitourinary tract (ureters and urethra), causing post-renal chronic insufficiency and uremic syndrome in short-finned pilot whales (Globicephala macrorhynchus) stranded between 2013 and 2018 in the Canary Islands. In this period of time 316 cetaceans stranded along the coasts of the Canary Islands, 224 of them were necropsied (70.9%), 25 belonged to the Globicephala macrorhynchus species (7.9%) but only 15 of them could be necropsied (4.75%), 7 of them were adults (2.22%), 7 were subadults and juveniles (2.22%), and 1 was a calf (0.32%); out of the 7 adults, 5 of them were males (1.58%), and 2 of them are relevant to our study. The prevalence of Crassicauda spp associated with uremic syndrome in 224 necropsied cetaceans between 2013 and 2018 in the Canary Islands is 0,98. The prevalence of this pathology in short-finned pilot whales stranded and necropsied during the same period and location is 13,33. Both specimens presented malnutrition, stomatitis, glossitis, multiple digestive tract ulcers and vascular alterations related to post-renal chronic insufficiency and uremic syndrome, presumably caused by the elevated number of Crassicauda spp. found obstructing the ureters and urethra. The harmful consequences of the lesions caused by the obstruction of this parasite, suggests that this parasitosis could be the cause of death in CET 643, and even though CET 920 died due to the active stranding process, the described pathology probably contributed to its stranding. There are not many cases of stranded cetaceans described whose cause of death is related to the uremic syndrome caused by the obstruction of Crassicauda, therefore this study tries to compare our specimens’ findings to the literature that has already been published about the infestation of this parasite in different organs and systems of cetaceans.