Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2003
Publication Date: 6/20/2003
Citation: DUBEY, J.P., GRAHAM, D.H., DAHL, E., SREEKUMAR, C., LEHMANN, T., DAVIS, M.F., MORISHITA, T.Y. 2003. TOXOPLASMA GONDII ISOLATES FROM FREE RANGING CHICKENS FROM THE UNITED STATES. JOURNAL OF PARASITOLOGY. 89:1060-1062. 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 Toxoplasmosis (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 the U.S. for the first time. These results will be of interest to public health workers, parasitologists and veterinarians.
Technical Abstract: Prevalence of Toxoplasma gondii infection in chickens is a good indicator of the strains prevalent in their environment because they feed from ground. The prevalence of T. gondii was determined in 118 free-range chickens from 14 counties in Ohio and from 11 chickens from a pig farm in Massachusetts. Toxoplasma gondii antibodies (¿1:5) were found with the modified agglutination test (MAT) in 20 of 118 chickens from Ohio. Viable T. gondii was recovered from 11 of 20 seropositive chickens by bioassay of their hearts and brains into mice. The parasite was not isolated from tissues of 63 seronegative (¿1:5) chickens by bioassay in cats. Hearts, brains, and muscles from legs and breast of the 11 chickens from the pig farm in Massachusetts were fed each to a T. gondii-negative cat. Eight cats fed chicken tissues shed oocysts; the 3 cats that did not shed oocysts were fed tissues of chickens with MAT titers of 1:5 or less. Tachyzoites of 19 isolates of T. gondii from Ohio and Massachusetts were considered avirulent for mice. Of 19 isolates genotyped, 5 isolates were type II, 14 were type III; mixed types and type I isolates were not found.