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United States Department of Agriculture

Agricultural Research Service


item Dubey, Jitender
item Vianna, M C B
item Sousa, S
item Canada, N
item Meireles, S
item Correia Da Costa, J
item Marcet, P
item Lehmann, T
item Darde, M
item Thulliez, P

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2005
Publication Date: 2/10/2006
Citation: Dubey, J.P., Vianna, M., Sousa, S., Canada, N., Meireles, S., Correia Da Costa, J.M., Marcet, P.L., Lehmann, T., Darde, M.L., Thulliez, P. 2006. Characterization of toxoplasma gondii isolates in free-range chickens from portugal. Journal of Parasitology. 92:184-186.

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. of Porto, Portugal report for the first time genetic characterization of Toxoplasma isolates from chickens from Portugal. 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 225 free-range chickens (Gallus domesticus) from Portugal was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 61 chickens with titers of 1:5 in 8, 1:10 in 6, 1:20 in 3, 1: 40 in 23, 1: 80 in 5, 1:160 in 4, 1:320 in 8, and 1: 640 or higher in 4. Hearts, leg muscles, and brains of 15 seropositive (MAT 1:10 or higher) chickens were bioassayed individually in mice. Tissue from 38 chickens with titers of 1:5 or less were pooled and fed to a T. gondii-free cat. Feces of cats were examined for oocysts, but none was found. Toxoplasma gondii was isolated from 16 of 19 chickens with MAT titers of 1:10 or higher. Genotyping of 12 of these 16 isolates using polymorphisms at the SAG2 locus indicated that 4 were Type III, and 8 were Type II. None of the isolates was lethal for mice. Phenotypically, T. gondii isolates from chickens from Portugal were different than those from T. gondii isolates from chickens from Brazil.

Last Modified: 06/23/2017
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