Skin of the Baikal Seal (Pusa Sibirica, Phocidae): Norm and Pathology

The study of 12 Baikal seals' skin reveals normal features such as a folded epidermis, hyperkeratosis, and distinct collagen layers, which aid in hydrodynamics, thermoregulation, and sun protection. Pathological findings include koilocytosis, subepidermal inflammation, and blister formation with neutrophilic infiltration. These issues may be related to global warming and changes in Lake Baikal's ice regime, possibly triggering immune responses, with a potential unknown viral pathogen causing koilocytosis.