Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 3, 1998
Publication Date: N/A
Interpretive Summary: Humans become infected with the single-celled parasite Toxoplasma gondii by ingesting tissue cysts from uncooked infected meat or by ingesting food and water contaminated with feces of infected cats. In 1995, a large outbreak of clinical toxoplasmosis occurred in people in Victoria, British Columbia, Canada. Water from a local reservoir was suspected as the source of infection. Scientists at the Beltsville Agricultural Research Center and Western College of Veterinary Medicine, University of Saskatchewan, Canada found T. gondii oocysts in 2 of 12 cougar (Felis concolor) fecal samples near the water reservoir providing a link to the human outbreak. These results will be of interest to public health workers, veterinarians, parasitologists and wildlife biologists.
One of 12 necropsied cougars (Felis concolor vancouverensis) from Vancouver Island, British Columbia, Canada, shed Toxoplasma gondii oocysts confirmed by mouse bioassay. Eleven of the 12 cougars (92%) had antibodies to T. gondii by the modified agglutination test with titers of <1:25 (1 cougar), 1:50 (8 cougars), and ò1:500 (3 cougars). One additional cougar fecal sample collected from the Victoria watershed environment also contained T. gondii oocysts. In 1995, the largest reported outbreak of human toxoplasmosis was linked to municipal drinking water in Victoria, British Columbia. This study supports the initial hypothesis at the time of the outbreak that not only domestic cats, but also cougars, pose a risk to Victoria's water supply.