Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 10, 1998
Publication Date: N/A
Interpretive Summary: Infections by the single-celled parasite, Toxoplasma gondii are widely prevalent in man and animals throughout the world. Toxoplasma gondii infections in humans are generally asymptomatic except in congenitally infected children and immunosuppressed individuals. It causes abortion in livestock. Some species of animals are more susceptible to clinical toxoplasmosis than others. Rats are considered one of the most resistant species whereas mice are one of the most susceptible hosts for T. gondii. Thus, infection in rats simulates infections in adult humans. Scientists at the Beltsville Agricultural Research Center has found that rats can be infected with as few as 1 viable Toxoplasma parasite. The utility of the rat as model animal for toxoplasmosis is described. This information will be useful to biologists and parasitologists.
Infectivity of Toxoplasma gondii bradyzoites was compared in outbred female Sprague Dawley rats and outbred Swiss Webster mice. Rats inoculated subcutaneously with 1 to 10 bradyzoites of the 2 strains of T. gondii (VEG and GT-1) developed persistent infection, whereas an infective dose by the oral route was 10 to 1,000 bradyzoites. The infectivity of bradyzoites of the VEG and the GT-1 strains of T. gondii in rats by the subcutaneous rout was comparable to that in mice.