Submitted to: Journal of Wildlife Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/27/2004
Publication Date: 3/10/2004
Citation: Measures, L.N., Dubey, J.P., Labelle, P., Martineau, D. 2004. Seroprevalence of toxoplasma gondii in canadian pinnipeds. Journal of Wildlife Diseases. 40:294-300. Interpretive Summary: Infection by the single celled parasite Toxoplasma gondii causes mental retardation and loss of vision in children. Cats are the only reservoir hosts that shed a resistant form of the parasite (oocyst) in feces. Scientists at the Beltsville Agricultural Research Center and a Fisheries Department in Canada report T. gondii infection in seals and suggest that T. gondii infection can be used to monitor contamination of the marine environment. These results will be of interest to biologists, parasitologists, and marine parasitologists.
Technical Abstract: Sera (N = 328) collected from phocids (1995-1997) from the east coast of Canada including harp seals (Phoca groenlandica), hooded seals (Cystophora cristata), grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina) were diluted 1:25, 1:50 and 1:500 and tested using a modified agglutination test for antibodies to Toxoplasma gondii. Titers equal to or greater than 1:25 were considered evidence of exposure. Grey seal (11/122 or 9.0%), harbour seal (3/34 or 8.8%), and hooded seal (1/60 or 1.7%) had titers of 1:25 and 1:50. Harp seals (N=112) were seronegative. Probable maternal antibody transfer was observed in one harbour and one grey seal pup 10 and 14 d of age, respectively. Transmission of T. gondii in the marine environment is not understood. The discovery of T. gondii in marine mammals may indicate natural infections unknown due to lack of study or may indicate recent contamination of the marine environment from the terrestrial environment due to natural or anthropogenic activities.