A 10-year-old male Atlantic bottlenose dolphin (Tursiops truncatus) died suddenly. Gross necropsy findings revealed an animal in good nutritional condition with hemorrhage and fibrosis of the anterior lung lobe, and hemorrhage in the right cerebrum, cerebellum, and right eye. Histological findings consisted of moderate multifocal acute necrotizing meningoencephalitis with intralesional fungal hyphae, dilated meningeal vessels with occasional transmural fungal elements, multifocal moderate cardiomyocyte degeneration and fibrosis, mild focal degeneration of the Purkinje fibers, and moderate diffuse acute congestion with patchy areas of edema and hemorrhage to the lung. Many cases of Apophysomyces elegans have been seen along the gulf coast. Since cerebral and cerebellar hemorrhage was consistent with this fungal disease, several pieces of tissue were sent to the Fungus Testing Laboratory in San Antonio, TX. Culture revealed Fusarium oxysporum which was confirmed with DNA testing. F. oxysporum is a common plant pathogen as well as an infectious agent to humans and other animals. Most reports of this fungus in animals and humans involve superficial dermatological or corneal infections. Human systemic cases occur in severely immunosuppressed patients. The source of many of these infections is found in the hospital water distribution systems. Several cases have been reported in marine mammals, but most of these cases are dermatological. No cases of systemic F. oxysporum in an apparently healthy cetacean have been reported in the literature.
The authors wish to the thank Annette W. Fothergill and Deanna A. Sutton from the Fungus Testing Laboratory for all of their hard work.