Viral skin diseases in odontocete cetaceans: gross, histopathological, and molecular characterization of selected pathogens

SIMONE SEGURA GÖTHLIN; ANTONIO FERNÁNDEZ; MANUEL ARBELO; MARISA ANDRADA; JAVIER ALMUNIA; IDARIA FELIPE JIMÉNEZ; ANA COLOM; CARLA FIORITO; EVA SIERRA

Conferencia; 34th European Cetacean Society Conference; 2023

55 skin lesions from 31 stranded cetaceans along the Canary coasts (2011-2021) were yield under macroscopical, histological, and molecular analysis to corroborate infection. Macroscopically, skin lesions were classified according to their color, shape, size, and consistency, obtaining in this manner the following eight categories and subcategories: tattoo-like (oval-shaped, coalesced, and serpiginous); black and white-fringed, pale; ulcerative; target-like; ring; and tortuous. Regarding molecular results, cetacean poxvirus was detected in 54.54% of the skin lesions through real-time and conventional PCRs based on the DNA polymerase gene. Additionally, molecular isolation of herpesvirus and morbillivirus in 43.63% and 1.82% of the cutaneous lesions were also achieved, respectively. As an exceptional finding, coinfection of poxvirus and herpesvirus was detected in nine of them (16.36%), being the first report of comorbidity of both pathogens in skin lesions in cetaceans. Microscopically, hyperkeratosis, acanthosis, and intracellular oedema as well as ballooning degeneration and intracytoplasmic inclusion bodies in vacuolized keratinocytes through stratum spinosum were common histopathological findings in poxvirus skin lesions. Herpesvirus was characteristically associated with prominent acanthotic epidermis with fused rete ridges, and moderate vascular congestion with predominantly neutrophilic inflammatory cell infiltration. Besides, distinctively necrosis, dyskeratosis, and irregular keratinocytes with both cellular and nuclei pleomorphism were remarked. In coinfected lesions, common histopathological findings of both pathogens were noted, being those prompted from herpesvirus significantly more appreciated. Intending to characterize skin lesions in a versatile perspective, lesions that presented tattoo-like patterns and those that displayed tortuous tracts, showed correlation between gross, molecular, and microscopic observations. Further multidisciplinary diagnostic studies of infected skin lesions are needed to understand the mechanisms of pathogenicity and host-pathogen dynamics of these emerging diseases.