Citation: Ragozo, A., L.E.O, Y., Oliveira, L., Dias, R., Dubey, J.P., Gennari, S. 2008. Seroprevalence and isolation of Toxoplasma gondii from sheep from Sao Paulo State, Brazil. Journal of Parasitology. 94:1259-1263. Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating undercooked meat from infected animals and food and water contaminated with oocysts. Scientists at the Beltsville Agricultural Research Center and University of Sao Paulo, Brazil report characteristics of Toxoplasma gondii isolates from sheep from Brazil.. These findings will be of interest to biologists, public health workers and parasitologists.
Technical Abstract: Sheep are important in the epidemiology of Toxoplasma gondii infection but little is known of ovine toxoplasmosis in Brazil. Antibodies to T. gondii were assayed in sera of 495 sheep from 36 counties of São Paulo State, Brazil, using the modified agglutination test (MAT titer =1:25) and found in 120 (24.2%). Samples of brain, heart, and diaphragm of 82 seropositive sheep were pooled, digested in pepsin, and bioassayed in mice. Toxoplasma gondii was isolated from tissue homogenates of 16 sheep and the isolates were designated TgShBr1-16. Six of the 16 T. gondii isolates killed 100% of infected mice. Results indicate that asymptomatic sheep can harbor mouse-virulent T. gondii, and hence they can serve as a source of infection for humans.