Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 10, 2005
Publication Date: December 10, 2005
Citation: Dubey, J.P., Rajapakse, R.J., Ekanayake, D.K., Sreekumar, C., Lehmann, T. 2005. Isolation and molecular characterization of Toxoplasma gondii from chickens from Sri Lanka. Journal of Parasitology. 91:1480-1482.
Interpretive Summary: Infection by the single-celled parasite, Toxoplasmaa gondii, is common in man and animals. Humans become infected by eating undercooked infected meat or ingesting the resistant stage of Toxoplasma (oocysts) 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 Sri Lanka. These results will be of interet 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 in 100 free-range chickens (Gallus domesticus) from Srilanka was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT). Antibodies were found in 39 chickens with titers of 1:5 in 8, 1: 10 in 8, 1:20 in 4, 1: 40 in 5, 1: 80 in 5, 1: 160 in 5, 1: 320 in 2, 1: 640 or more in 2. Hearts and brains of 36 chickens with MAT titers of 1:5 or more were bioassayed in mice. Tissues of 3 chickens with doubtful titers of 1:5 were pooled and fed to a cat; the cat shed T. gondii oocysts in its feces. Tissues from 61 chickens with titers of less than 1:5 were pooled and fed to 2 T. gondii-free cats; the cats did not shed oocysts. Toxoplasma gondii was isolated from 11 of 36 seropositive chickens by bioassay in mice. All 12 T. gondii isolates were avirulent for mice. Genotyping of 12 isolates using the SAG2 locus indicated that 6 were Type III, and 6 were Type II. This is the first report of genetic characterization of T. gondii from any host from Sri Lanka.