Submitted to: Journal of Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/10/2002
Publication Date: 9/11/2002
Citation: Resendes, A.R., Almeria, S., Dubey, J.P., Obon, E., Juan-Salles, C., Degollada, E., Alegre, F., Cabezon, O., Pont, S., Domingo, M. 2002. Disseminated toxoplasmosis in a mediterranean pregnant risso's dolphin (grampus griseus) with transplacental fetal infection. Journal of Parasitology 88:1029-1032. Interpretive Summary: Infections by the single-celled parasite Toxoplasma gondii are widely prevalent in animals and humans. It causes mental retardation and loss of vision in congenitally-infected children. It is also a significant cause of mortality in zoo animals. Scientists at the Beltsville Agricultural Research Center and the University in Barcelona, Spain report fatal toxoplasmosis in the mother dolphin and in her fetus for the first time. These results will be of interest to wildlife biologists, parasitologists and pathologists.
Technical Abstract: Fatal disseminated toxoplasmosis was diagnosed in a Risso's dolphin (Grampus griseus) dam and its fetus based on pathologic findings, immunohistochemistry, and the structure of the parasite. The dolphin was stranded alive on the Spanish Mediterranean coast, and died a few hrs later. At necropsy the dam was in good condition. From the standpoint of pathology, however, it had generalized lymphadenomegaly and splenomegaly, enlargement and multifocal hemorrhage in the adrenal glands, diffuse mucosal hemorrhage of the glandular and pyloric stomach, ulcerative glossitis and stomatitis, focal erosions and reddening of the laryngeal appendix, and severe paraotic sinusitis with intralesional nematodes Crassicauda grampicola. The dolphin was pregnant, most probably in the first gestational trimester. The most prominent microscopic lesions were multifocal granulomatous encephalomyelitis, diffuse subacute interstitial pneumonia, mild multifocal necrotizing hepatitis and nonsuppurative cholangiohepatitis, gastritis and adrenalitis, mild lymphoid depletion, medullary sinus and follicular histyocitosis, and systemic hemosiderosis. The fetus had foci of coagulative and lytic necrosis in the kidneys, lung, and heart. Most lesions were associated with tachyzoites and tissue cysts of Toxoplasma gondii. The diagnosis was confirmed immunohistochemically. This is the first report of toxoplasmosis in a Risso's dolphin (Grampus griseus) and of transplacental transmission to an early stage fetus in any cetaceans.