Muscle Pathology in Free-Ranging Stranded Cetaceans

Area of Science:

• Veterinary Pathology
• Marine Mammal Science
• Comparative Myology

Background:

• Skeletal muscle disorders can significantly impair marine mammal function.
• Such conditions are infrequently documented in cetaceans.
• Understanding muscle pathology is crucial for assessing cetacean health.

Purpose of the Study:

• To investigate the prevalence and types of skeletal muscle lesions in odontocetes and mysticetes.
• To establish the diagnostic value of skeletal muscle examination in stranded cetaceans.

Main Methods:

• Macroscopic evaluation of epaxial muscle mass in 153 cetaceans across 19 species.
• Histological examination of the longissimus dorsi muscle.
• Analysis of macroscopic and microscopic findings.

Main Results:

• Macroscopic findings were limited to muscle atrophy in emaciated individuals.
• Histopathology revealed significant lesions in 91.5% of cases.
• Common lesions included degenerative changes (75.2%), atrophy (37.9%), chronic myopathic changes (25.5%), parasitic infestation (9.2%), and myositis (1.9%).

Conclusions:

• Skeletal muscle lesions are highly prevalent in stranded cetaceans.
• Histopathological examination of skeletal muscle provides valuable diagnostic information.
• Systematic muscle sampling during necropsy is recommended for all stranded cetaceans.