Submitted to: Journal of Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/5/2009
Publication Date: 5/1/2009
Citation: Dubey, J.P., Velmurugan, G.V., Alvarado-Esquivel, C., Alvarado-Esquivel, D., Rodriquez-Pena, S., Martinez-Garcia, S., Gonzalez-Herrara, A., Ferreira, L.R., Kwok, O.C., Su, C. 2009. Isolation of Toxoplasma gondii from animals in Durango, Mexico. Journal of Parasitology. 95:319-322. 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 an university in Mexico report the first genetic characterization of Toxoplasma from animals in Mexico. The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: Little is known concerning the epidemiology of Toxoplasma gondii infection in people and animals in rural Mexico. Serum samples and tissues from 150 dogs, 150 cats, 65 opossums (Didelphis virginianus), 249 rats (Rattus spp.), 127 mice (Mus musculus), and 69 squirrels (Spermophilus variegatus) from the Durango area were evaluated for T. gondii infection. Using a modified agglutination test and a serum dilution of 1:25, antibodies to this parasite were found in 14 (9.3%) of 150 cats, 68 (45.3%) of 150 dogs, 2 (0.8%) of 249 rats, 4 (3.1%) of 127 mice, 0 of 69 squirrels, and 11 (16.6%) of 66 opossums. Tissues (brains and hearts) of cats, dogs, opossums, rats, mice, and squirrels were bioassayed in mice for the presence of T. gondii. Viable T. gondii was isolated in tissues from 3 of 28 seropositive dogs, and 5 of 8 seropositive cats, but not from other animals. The DNA obtained from the 3 T. gondii isolates from dogs, 6 isolates from 5 cats, and 4 isolates from free-range chickens from Mexico previously isolated were genotyped. The PCR-RFLP typing using 11 markers (B1, SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) identified 5 genotypes. One genotype (the 4 chicken isolates) belongs to the clonal Type III lineage. Three genotypes were reported in previous reports, and 1 genotype is unique.