Fatal aspergillosis and evidence of unrelated hearing loss in a harbor porpoise (Phocoena phocoena) from the German Baltic Sea

Detailed post-mortem investigations including the auditory pathway are needed to advance our understanding of how underwater noise and other stressors affect hearing in cetaceans. A 12-year-old female porpoise ( Phocoena phocoena ) stranded alive June 2021 at German Baltic Sea coast died some hours later. The most significant pathological findings were lesions caused by a severe aspergillosis that spread from lung pulmonary lymph node cerebellum. Based on molecular sequencing, fungus was identified as Aspergillus fumigatus. Severe pyogranulomatous necrotizing inflammation diagnosed associated node. In left part cerebellum, focal, purulent meningoencephalitis with intralesional fungal structures confirmed histologically. addition, multifocal, severe, chronic, granulomatous, eosinophilic gastritis parasite found stomach. Parallel stripes (linear skin markings) detected along caudal both body sides, which have not been previously described for harbor porpoises. Inner ear analysis revealed evidence focal loss outer hair cells several regions 120 580 µm apex right cochlea using immunofluorescence. low-frequency impairment compatible noise-induced loss. This is first case concurrent presumptive unrelated free-ranging porpoise.