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The objective was to characterize the transmission of Toxoplasma gondii in goats experimentally infected vaginally with semen contaminated with the CPG strain (genotype III). Ten female goats were randomly allocated into 2 groups (G1 and G2), each with 5 animals, and inseminated during estrus. Goats in G1 were inseminated with semen containing 1 × 10(5) tachyzoites, whereas those in G2 (control) were inseminated with semen free from tachyzoites (insemination = day 0). In G1, seroconversion (indirect immunofluorescence reaction) and DNA (polymerase chain reaction) in the blood was present in 4/5 and 3/5, respectively, from the 7th day. In G2, all goats were negative in all tests. Embryonic reabsorption occurred in 4 of 5 goats from G1 between days 21 and 49. In conclusion, artificial vaginal insemination with semen containing tachyzoites of T. gondii -infected goats and is a potential transmission route of this parasite through semen.

Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete environmentally resistant oocysts. The prevalence of T. gondii was determined in 58 domestic cats from 51 homes from Santa Isabel do Ivai, Parana State, Brazil where a water-associated outbreak of acute toxoplasmosis had occurred in humans. Antibodies to T. gondii were found with the modified agglutination test in 49 of 58 (84.4%) cats at a serum dilution of 1:20. Tissues (brain, heart, and skeletal muscle) of 54 of these cats were bioassayed in T. gondii-free, laboratory-reared cats; T. gondii oocysts were excreted by 33 cats that were fed feline tissues. Brains from these 54 cats were bioassayed in mice; T. gondii was isolated from 7. Skeletal muscles and hearts of 15 cats were also bioassayed in mice; T. gondii was isolated from skeletal muscles of 9 and hearts of 13. The results indicate that T. gondii localizes in muscle tissue more than the brains of cats. In total there were 37 T. gondii isolates from 54 cats. Most isolates of T. gondii were virulent for mice. Genotyping of the 37 isolates of T. gondii, using the SAG2 locus, revealed that 15 isolates were type I and 22 were type III. The absence of type II genotype in cats in this study is consistent with the previous studies on T. gondii isolates from Brazil and is noteworthy because most T. gondii isolates from the United States are type II. These findings support the view that Brazilian and North American T. gondii isolates are genetically distinct. This is the first report of genotyping of T. gondii isolates from the domestic cat.