Lungworm infection with Otostrongylus circumlitus in a free-ranging harbor seal (Phoca vitulina)

A young wild harbor seal (Phoca vitulina) was found stranded on the North Sea coast at Koksijde (Belgium)and was admitted to a rehabilitation center where it died one day later. Full necropsy with histopathology was performed. Gross examination revealed severe diffuse hemorrhagic and emphysematous pneumonia with the presence of 6-10 cm-large nematodes. The nematodes were found in the trachea, large bronchi, right heart and pulmonary arteries, and subsequently identified as Otostrongylus circumlitus. Histologic examination demonstrated severe eosinophilic to granulomatous bronchointerstitial pneumonia with intralesional nematodes. It was concluded that the seal died of severe verminous pneumonia. In this case report, the importance of lungworm infection, which is a common and critical disease in young seals, is highlighted