First report on Phyllobothrium delphini infection and Crassicauda sp. parasitism resulting in osseous metaplasia in a Cuvier's beaked whale (Ziphius cavirostris) from the Brazilian region

Abstract

A female Cuvier's Beaked Whale ( Ziphius cavirostris ) specimen measuring 580 cm in length died after being stranded in Southeastern Brazil. Following a necropsy, organ samples were obtained, fixed in 10% neutral buffered formalin and histopathologically analyzed. A severe and generalized hypodermis infection by Phyllobothrium delphini (Phyllobothriidae) was observed, resulting in granulomatous panniculitis. Severe renal and arterial lesions were also noted, including a severe bone metaplasia in the aorta artery, associated with a massive infection by Crassicauda sp, (Tetrameridae). A significant thoracic hemorrhage due to thoracic aorta artery rupture was noted, also likely due to this infection, resulting in a fatal injury. This study contributes towards knowledge on histopathologic changes in the scarcely studied Cuvier's Beaked Whale, is the first to associate a Crassicauda sp. infection in this whale species in the Brazilian region and also the first to indicate a resulting osseous metaplasia due to this parasitism and granulomatous dermatitis associated with Phyllobothrium delphini . Furthermore, this is also, to the best of our knowledge, the first report of Phyllobothrium delphini cysts in a Ziphius cavirostris specimen to date.

Molecular characterization of the parasitic nematode genus Crassicauda; larvae parasitic on the firefly squid and adults on beaked whales off the coast of Japan

“…On the other hand, C. anthonyi was detected only from Z. cavirostris . These results, together with other reports ( Febronio et al, 2021 ; Jerdy et al, 2022 ), strongly suggest that C. anthonyi only infects to Z. cavirostris and is distributed worldwide. Interestingly, Crassicauda sp.…”

“…Each Crassicauda is a tissue-specific parasite of the kidneys, genitalia, intracranial sinuses and subcutaneous tissue, causing pathogenicity in each of these tissues. Along with C. boopis in fin whale, C. giliakiana in Baird's beaked whale ( Berardius bairdii ) and beluga ( Delphinapterus leucas ), and C. anthonyi in Cuvier's beaked whale ( Ziphius cavirostris ) infect the kidneys, they shed their eggs in the urine, especially with severe and widespread chronic renal granulomatous and fibrotic interstitial nephritis with kidney atrophy and loss due to nematode infection ( Marcer et al, 2019 ; Burek-Huntington et al, 2015 ; Febronio et al, 2021 ; Jerdy et al, 2022 ).…”

Morganella morganii septicemia and concurrent renal crassicaudiasis in a Cuvier’s beaked whale (Ziphius cavirostris) stranded in Italy

“…Parasitic disease due to Crassicauda spp. has been increasingly reported as a significant cause of death in beaked whales (Dıáz-Delgado et al, 2016;Febronio et al, 2021;Jerdy et al, 2022) and other cetaceans (Balbuena and Simpkin, 2014) worldwide. For most of the 14 species of the genus, life cycle and transmission are still unclear.…”

“…These nematodes show different tissue tropisms (urogenital, vascular, integumentary, respiratory) and pathogenic potential, playing a regulatory role in some marine mammal populations (Balbuena and Simpkin, 2014). Crassicauda boopis causes severe renal lesions in baleen whales (Lambertsen, 1986;Marcer et al, 2019), C. grampicola is associated with moderate to severe sinusitis in Risso's dolphins (G. griseus) (Cuvertoret-Sanz et al, 2020) whereas C. anthonyi and C. magna migration produces verminous arteritis and chronic renal disease in beaked whales (Dıáz-Delgado et al, 2016;Febronio et al, 2021;Jerdy et al, 2022). Moreover, several species of crassicaudid nematodes, including C. grampicola (Geraci et al, 2011) and C. fuelleborni (Kot et al, 2022) produce parasitic mastitis impacting the reproductive success of endangered cetaceans.…”