Verminous Arteritis Due to Crassicauda sp. in Cuvier’s Beaked Whales (Ziphius Cavirostris)

Abstract

The vascular system of Cuvier's beaked whales (CBW) (Ziphius cavirostris; family Ziphiidae), an extremely deep, prolonged-diving cetacean, is increasingly receiving anatomic and physiologic study due to possible anthropogenic interactions; however, vascular pathology rarely has been reported in this species. Thirteen CBW stranded in the Canary Islands from June 2008 to June 2014 were autopsied. A careful dissection of the thoracic and abdominal vasculature was performed on these animals. All had moderate to severe and extensive chronic fibrosing arteritis with aneurysms, hemorrhages, and thrombosis primarily involving the mesenteric and gastroepiploic arteries and the thoracic and abdominal aorta. Microscopically, the lesions varied from subacute subintimal hemorrhages and severe neutrophilic, eosinophilic, and histiocytic dissecting arteritis with intralesional nematode larvae to marked, chronic, fibrosing arteritis with thickening and distortion of the vascular wall with calcification and occasional cartilage metaplasia. In addition, adult nematodes in renal arteries and veins, renal parenchyma and/or ureter were identified morphologically as Crassicauda sp. Nucleic acid sequenced from renal nematodes from 2 animals yielded closest nucleotide identity to C. magna The pathogenesis is proposed to involve a host response to larval migration from the intestine to the kidney through the mesenteric arteries, abdominal aorta, and renal arteries. Severe consequences for such lesions are possible and could vary from reduced vascular compliance to chronic renal disease and predisposition to the development of disseminated intravascular coagulation and multiorgan failure. Severe chronic arteritis in CBW is associated with renal parasitism by Crassicauda spp.

Crassicauda boopis in a fin whale (Balaenoptera physalus) ship-struck in the eastern North Atlantic Ocean

“…Consensus sequence of 18S rRNA gene obtained from these present samples was similar to the sequence obtained from parasites found in subcutaneous tissues of a pygmy sperm whale (Kogia breviceps) and identified as C. magna (Jabbar et al 2015). Additionally, this sequence was similar to the partial sequence of a worm located in the kidney of a Cuvier's beaked whale (Ziphius cavirostris) (Díaz-Delgado et al 2016). While adults of C. boopis and C. magna are morphologically distinct and found in different body sites, molecular analysis of the 18S rRNA gene seems insufficient for reliable species identification.…”

Diseases and parasites

“…Predominant gross renal lesions in bowhead whales with mild to severe crassicauda infection include renal arteritis with and without partial lumen occluding thrombi, single to multiple renal granulomas and renal cysts (Stimmelmayr and Rotstein, unpublished data). Such lesions are similar to what has been described for Cuvier beaked whales ( Díaz-Delgado et al, 2016 ) and less similar to what has been reported for fin, humpback, and blue whales ( Lambertsen, 1986 ). Results from analysis of limited serum chemistry for two bowhead whales (NSB-DWM 2016B16 and 2016B22) suggest that renal lesions were unlikely to have impacted renal function.…”

Pathologic findings and causes of death of stranded cetaceans in the Canary Islands (2006-2012)

“…46, 126 and 131 Severe arterial and renal crassicaudiasis was diagnosed in five Cuvier’s beaked whales (CBW; Ziphius cavirostris ) (animal no. 92, 118, 180, 167 and 207) [ 22 ]. Severe pterygoid sinusitis by Nasitrema sp.…”

“…Severe arterial and renal crassicaudiasis was observed in five CBW in this group [ 22 ]. Crassicauda magna was identified in two of them.…”

“…Crassicauda magna was identified in two of them. Severe arterial lesions could result in fatalities from disseminated intravascular coagulation, multisystemic failure and severe renal damage, or major aggravation of coexisting disease [ 22 ]. Severe pterygoid sinusitis by Nasitrema sp.…”