Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 12, 1997
Publication Date: N/A
Interpretive Summary: Infection by the single-celled parasite, Toxoplasma gondii are widespread in humans and livestock. It causes mental retardation and loss of vision in children and abortion in livestock. Cats are the only host that excrete the resistant stage (oocyst) of T. gondii. Recent epidemiological evidence from Panama suggested that association with dogs was positively correlated with human infections yet dogs do not excrete T. gondii oocysts. Scientists at the Beltsville Agricultural Research Center and the Auburn University have found that dogs do roll over in cat feces, and this can mechanically spread T. gondii oocysts in the environment. These results will be useful to public health workers, veterinarians and parasitologists in general.
Two experiments were conducted to determine if dogs could mechanically transmit Toxoplasma gondii after ingesting cat feces or by rolling in cat feces containing oocysts. In the first experiment, 2 dogs were fed sporulated T. gondii oocysts; viable sporulated oocysts were present in dog feces for up to 2 days postinoculation. Both dogs seroconverted to T. gondii but did not develop clinical signs of toxoplasmosis. In the second experiment, nonsporulated oocysts were placed on dog skin and fur and fur clippings were bioassayed for T. gondii in mice. Oocysts did not sporulated on dog fur. Results of this study support the hypothesis that dogs may be involved in the mechanical transmission of T. gondii to humans.