Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 2004
Publication Date: April 15, 2004
Citation: Dubey, J.P., Levy, M.Z., Sreekumar, C., Kwok, O.C., Shen, S.K., Dahl, E., Thulliez, P., Lehmann, T. 2004. Tissue distribution and molecular characterization of chicken isolates of Toxoplasma gondii from Peru. Journal of Parasitology. 90(5):1015-1018.
Interpretive Summary: Infection by the single-celled parasite, Toxoplasma gondii, is common in man and animals. Humans become infected by eating undercooked infected meat or ingesting the resistant stage of Toxopoasma (oocyts) in the environment. Infections in free range-range chickens is indicative of Toxoplasma infection in the environment because chickens feed from the ground. Scientists at the Beltsville Agricultural Research Center and Centers for Disease control, Atlanta, Georgia, report isolation and molecular characterization of Toxoplasma gondii strains from free-range chickens from Peru. These results will be of interest to public health workers, parasitologists and veterinarians.
The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii antibodies in sera of 50 free- range chickens (Gallus domesticus) from Peru was 26% based on the modified agglutination test (MAT). Hearts, pectoral muscles, and brains of seropositive (MAT '1:5) chickens were bioassayed individually in mice. Tissues from the remaining 37 seronegative chickens were pooled and fed to 2 T. gondii-free cats. Feces of cats were examined for oocysts; they did not shed oocysts. Toxoplasma gondii was isolated from the hearts of 10 seropositive chickens but not from their brains and pectoral muscles. Genotyping of these isolates using the SAG2 locus indicated that 7 isolates were Type I and 3 were Type III. Six of the 7 Type I isolates were avirulent for mice, which was unusual, as Type I isolates are considered virulent for mice. The T. gondii isolates were from chickens from different properties that were at least 200 m apart. Thus, each isolate is likely to be different. This is the first report of isolation of T. gondii from chickens from Peru.