Fatal disseminated toxoplasmosis in a spinner dolphin (Stenella longirostris)

Toxoplasmosis is a common, mainly asymptomatic infection in warm-blooded mammals and birds. Among marine mammals, toxoplasmosis has been reported in several pinnipeds and a manatee but not in cetaceans. We report toxoplasmosis in a wild, free-living male spinner dolphin (Stenella longirostris ). The animal was 199 cm long and was found beached on Chun's Reef, Haleiwa, Oahu, Hawaii. Histopathology is discussed. In the parenchymal cells were numerous organisms of Toxoplasma gondii , including both tachyzoites and tissue cysts. The bradyzoites in tissue cysts stained positively with the periodic acid-Schiff technique.