Identification of Crassicauda anthonyi in renal lesions of Cuvier’s beaked whales (Ziphius cavirostris) stranded in Canary Island

Abstract

Cuvier's beaked whales (CBWs) (Ziphius cavirostris) are among the 31 different cetacean species identified in the Canary Islands Atlantic waters. Stranded CBWs usually show a high prevalence of nematode parasites of the genus Crassicauda affecting the kidneys and urinary tracts, as well as the arterial walls of the infected animals. However, no parasite identification has been carried out so far. With this aim, adult parasites were collected from the kidneys of 11 stranded dead CBWs with different conservation code (from 2 to 4). Morphological and molecular (a PCR targeting the mitochondrial gene cox1) identification were carried out. In addition, kidney samples were subjected to histopathological studies. As a result, the nematode Crassicauda anthonyi was molecularly identified in 4 animals (being the carcasses within the freshest conservation status) in agreement with the morphological parasitic identification. The renal nodular lesions were characterized by granulomatous processes of variable severity and extension which use to show intralesional nematodes, fibrosis, necrosis and multifocal mineralization. This study provides the first molecular identification of the nematode Crassicauda anthonyi as responsible for a high prevalence of renal and arterial lesions in CBWs stranded in the Canary Islands, contributing to improve the knowledge of crassicaudiasis in these cetacean species.