Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2004
Publication Date: 5/23/2004
Citation: Dubey, J.P., Navarro, T., Sreekumar, C., Dahl, E., Freire, R.L., Prudencio, L.B., Vianna, M.C., Kwock, C.H., Shen, S.K., Thulliez, P. 2004. Toxoplasma gondii infections in cats from Parana, Brazil: seroprevalence, tissue distribution, and biologic and genetic characterization of isolates. Journal of Parasitology. 90(4):721-726. Interpretive Summary: Infection by the single-celled parasite, Toxoplasma gondii, is common in man and animals. Humans become infected by eating undercoked infected meat or ingesting the resistant stage of Toxoplasma (oocysts) in the environment. Infections in cats is indicative of Toxoplasma infection in the environment. Scientists at the Beltsville Agricultual Research Center and Centers for Disease Control, Atlanta, Georgia, report isolation and molecular characterization of Toxoplasma gondii strains from cats from Brazil. These results will be of interest to public health workers, parasitologists and veterinarians.
Technical Abstract: Cats are important in the epidemiology of Toxoplasma gondii as they are the only hosts that can excrete environmentally-resistant T. gondii oocysts. The prevalence of T. gondii was determined in 58 domestic cats from 51 homes from Santa Isabel do Ivai, Paraná State, Brazil where a water-associated outbreak of acute toxoplasmosis had occurred in humans. Antibodies to T. gondii were found in 49 of 58 (84. 4%) cats at a serum dilution of 1:20 with the modified agglutination test. Tissues (brain, heart, and skeletal muscle) of 54 of these cats were bioassayed in T. gondii-free, laboratory-raised 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 the 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. Most isolates of T. gondii were virulent for mice. Genotyping of 35 of the 36 isolates of T. gondii, using the SAG 2 locus, revealed that 14 isolates were Type I, and 21 were Type III. The absence of Type II genotype in cats in the present study is consistent with the previous studies on T. gondii isolates from Brazil, and is noteworthy because most T. gondii isolates from the U. S. A. are Type II. These findings support the view that Brazilian and North American T. gondii isolates are genetically distinct.