Pathological and epidemiological investigation of skin lesions in belugas (Delphinapterus leucas) from the St. Lawrence Estuary, Quebec, Canada

Following the evaluation of 26,020 photographs collected from 2003 to 2014 as part of a photo-identification program in St. Lawrence Estuary belugas, an atlas of cutaneous anomalies, composed of 18 skin lesions categories (SLCs), is proposed. At least one SLC was present in 51%, 97%, and 94% of neonates, gray, and white belugas, respectively. The most common SLC observed were single linear fissure (22%), single linear scar (19%), and ulcer-like lesion (17%) in neonates, and rake mark (77%; 70%), single linear fissure (31%; 24%) and circular depression (40%; 35%) in gray and white belugas, respectively. Logistic regression modeling revealed significant correlations between temporal and individual variables for most SLCs. Histological evaluation of cutaneous lesions from 111 belugas stranded between 1983 and 2017 were also performed. Single linear fissure, single linear scar, crater-like scar, rake mark, and Morse code lesions appear to be of traumatic origin. Results from pathological and epidemiological analyses suggest that some of these SLCs, such as yellow patch, circular depression, and map depression are associated with molting. Postnatal molting could account for ulcer-like lesions and single linear fissures in neonates. Urchin spines were found within pinhole erosions and a gamma-herpesvirus was detected by PCR in a wound.

Automated summary

A study was conducted on cutaneous anomalies in St. Lawrence Estuary belugas, proposing an atlas of 18 skin lesions categories. Some skin lesions were found to be of traumatic origin or associated with molting, with confirmation through histological evaluation and epidemiological analysis.