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

Abstract

AbstractFollowing 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.