Submitted to: Veterinary Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/16/2005
Publication Date: 7/19/2005
Citation: Dubey, J.P., Edelhofer, R., Marcet, P., Vianna, M., Kwok, O.C., Lehmann, T. 2005. Genetic and biologic characteristics of Toxoplasma gondii infections in free-range chickens from Austria. Veterinary Parasitology 133:299-306. 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 Univ. Austria have found that T. gondii infection is widely prevalent in chickens from Austria. The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: 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 free-range chickens (Gallus domesticus) from 11 Bio-farms in Austria was determined. Antibodies to T. gondii assayed by the modified agglutination test (MAT) were found in 302 of 830 (36.3 %) chickens with titers of 1: 10 in 50, 1: 20 in 69, 1: 40 in 53, 1: 80 in 40, 1: 160 or higher in 90. Hearts of 218 chickens with MAT titers of 10 or higher were bioassayed individually in mice. Tissues from 1183 chickens were pooled and fed to 15, T. gondii-free cats. Feces of the cats were examined for oocysts; 11 cats shed T. gondii oocysts. Toxoplasma gondii was isolated from 56 chickens by bioassay in mice. Thus, there were 67 isolates of T. gondii from these chickens. Genotyping of 33 of these 67 isolates using the SAG2 locus indicated that all 33 were Type II. Phenotypically and genetically these isolates were different from T. gondii isolates from Brazil. None of the isolates was virulent for mice. This is the first report of isolation of T. gondii from chickens from Austria.