DEVELOPMENT OF AN INTEGRATED RISK MODEL FOR FOODBORNE ZOONOTIC PARASITES IN SWINE
Title: Genetic and biologic characterization of Toxoplasma gondii isolates of cats from China
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 2006
Publication Date: May 1, 2007
Citation: Dubey, J.P., Zhu, X.Q., Sundar, N., Zhang, H., Kwok, O.C., Su, C. 2007. Genetic and biologic characterization of Toxoplasma gondii isolates of cats from China. Veterinary Parasitology. 145:352-356.
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 an Univ. in China report first survey of T. gondii infection in cats in China. Results indicate that strains of Toxoplasma from cats from China are different from North America.The results will be of interest to biologists, parasitologists, and veterinarians.
Cats are important in the epidemiology of Toxoplasma gondii infection because they are the only hosts that can excrete the environmentally resistant oocysts. In the present study, prevalence of T. gondii was determined in serum, feces, and tissues of 34 cats from Peoples Republic of China. Antibodies to T. gondii were assayed by the modified agglutination test and found in of 27 of 34 (79.47 %) cats with titers of 1:10 in five, 1:40 in one, 1:80 in one, 1:160 in three, 1:320 in three, 1:640 in eight, and 1:1280 or higher in 11 cats. T. gondii oocysts were not found in feces of any cat as ascertained by bioassay in mice. Tissues (brain, heart, tongue) of 27 seropositive cats were bioassayed in mice or cats. T. gondii was isolated from tissues of 17 of 21 cats with titers of 1:40 or higher. Genotyping of these 17 T. gondii isolates using polymorphisms at 10 nuclear markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22 8, c29 2, L358, PK1 and a new SAG2, and an apicoplast marker Apico revealed two genotypes. This is the first report of genetic typing of T. gondii isolates from cats from China.