Transplacental Transmission of Toxoplasma gondii in Risso's Dolphin (Grampus griseus)
IAAAM Archive
Ana R. Resendes1; Mariano Domingo1; Sonia Almería2; J.P. Dubey3; Carles Juan-Sallés4; Eduard Degollada5; Elena Obón6; Ferran Alegre6; Oscar Cabezón6; Sara Pont6
1Histologia i Anatomia PatolÁgica, Facultat de Veterinària, Universitat AutÁnoma de Barcelona, Bellaterra, Spain; 2Parasitologia i Malalties Parasitàries, Facultat de Veterinària, Universitat AutÁnoma de Barcelona, Bellaterra,Spain; 3Parasite Biology, Epidemiology and Systematics Laboratory, Animal and Natural Resources Institute, Agriculture Research Service, United States Department of Agriculture, Beltsville, MD, USA; 4Departamento de Patología, Africam Safari, Puebla, México; 5Anatomia i Embriologia, Facultat de Veterinària, Universitat AutÁnoma de Barcelona, Bellaterra, Spain; 6Centre de Recuperació d' Animals Marins de Catalunya (CRAM), 08330 Premià de Mar (Barcelona), Spain


Toxoplasma gondii transplacental infection is described in man, sheep, goat, and pigs, and occurs when the dam acquires infection for first time during pregnancy.1 Transplacental infection can cause early embryonic death and reabsorption, fetal death and mummification, abortion, stillbirth and neonatal death, depending on the stage of pregnancy at which the infection takes place.1 In humans, babies become more severely affected when the mother is infected in early pregnancy.1 On the other hand, when it occurs in a later stage generally results in a neonatal subclinical infection.1 Toxoplasmosis has been previously reported in a wide variety of captive and wild marine mammals.4,7 Moreover, transplacental transmission was most probably the origin of T.gondii infection in some species of marine mammals: California sea lion (Zalophus californianus), Harbour seal (Phoca vitulina), bottlenose dolphin (Tursiops truncatus) and beluga whale (Delphinapterus leucas).5,8 Recently a stillborn Indo-pacific bottlenose dolphin (Tursiops aduncus) was diagnosed with congenital toxoplasmosis.6

This study confirms transplacental T. gondii transmission in a Risso's dolphin (Grampus griseus), where a disseminated toxoplasmosis was diagnosed in the dam and her fetus. The diagnosis was based on pathologic findings, immunohistochemistry, and the structure of the parasite. At necropsy the dam had a good body condition, 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. The dolphin was pregnant, most probably in the first gestational trimester (fetus 12.5 cm long). The most prominent microscopic lesions in the dam 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 histiocytosis. The fetus had foci of coagulative and lytic necrosis in the kidney, lung, and heart. Most lesions were associated with tachyzoites and tissue cysts of T. gondii, that stained positively with an anti-toxoplasma specific antibody.

In contrast with other species no gross placental lesions were observed. The fetus lesions were severe and similar in nature to others transplacental-infections reports.2,3,6 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. These findings indicate that toxoplasmosis should be included in the differential diagnosis of reproductive failure in cetaceans.


1.  Dubey JP, CP Beattie. 1988. Toxoplasmosis of animals and man. CRC Press, Boca Raton, Florida, 220 pp.

2.  Dubey JP, DH Schlafer, JF Urban Jr., DS Lindsay. 1990. Lesions in fetal pigs with transplacentally-induced toxoplasmosis. Veterinary Pathology 27: 411-418.

3.  Dubey JP, Mattix ME, TP Lipscomb. 1996. Lesions of neonatally induced toxoplasmosis in cats. Veterinary Pathology. 33: 290-295.

4.  Holshuh HJ, AE Sherrod, CR Taylor, BF Andrews, EB Howard, 1985. Toxoplasmosis in a feral northern fur seal. Journal of the American Veterinary Medical Association 187: 1229-1230.

5.  Inskeep II.W, CH Gardiner, RK Harris, JP Dubey, RT Goldston, 1990.Toxoplasmosis in Atlantic bottle-nosed dolphin (Tursiops truncatus). Journal of Wildlife Diseases 377-382.

6.  Jardine JE, JP Dubey, 2002. Congenital toxoplasmosis in a Indo-Pacific Bottle-Nose dolphin (Tursiops aduncus). Journal of Parasitology (in press)

7.  Lindsay DS, NJ Thomas, AC Rosypal, JP Dubey. 2001. Dual Sarcocystis neurona and Toxoplasma gondii infection in a Northern sea otter from Washington state, USA. Veterinary Parasitology 97: 319-327.

8.  Mikaelian I, J Boisclair, JP Dubey, S Kennedy, D Martineau, 2000. Toxoplasmosis in Beluga Whales (Delphinapterus leucas) from the St Lawrence Estuary: Two case reports and a serological survey. Journal of Comparative Pathology 122: 73-76.

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Ana R. Resendes

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