Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2007
Publication Date: 8/22/2007
Citation: Dubey, J.P., Webb, D.M., Sundar, N., Velmurugan, G.V., Bandini, L.A., Kwok, O.C., Su, C. 2007. Endemic avian toxoplasmosis on a farm in Illinois: clinical disease, diagnosis, biologic and genetic characteristics of Toxoplasma gondii isolates from chickens (Gallus domesticus), and a goose (Anser anser). Veterinary Parasitology. 148:207-212.
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.Toxoplasmosis causes mortality in many species of animals in the zoos, especially primates. Scientists at the Beltsville Agricultural Research Center and Univ. of Illinois document clinical toxoplasmosis in chickens and report genetic characterization of Toxoplasma from chickens from Illinois. The results will be of interest to biologists, parasitologists, and veterinarians
Technical Abstract: Clinical toxoplasmosis in chickens (Gallus domesticus) has been rarely reported in literature. Here we report that three chickens on a farm in Illinois developed neurological signs . One of these chickens was examined postmortem and it had non-suppurative encephalitis with numerous Toxoplasma gondii tachyzoites and tissue cysts. The identity of the protozoa was confirmed immunohistochemically by staining with T. gondii specific antibodies, and by transmission electron microscopy. The owner of the three chickens donated all 11 remaining chickens and a goose on his property for the present study. All 11 chickens and a goose were euthanized, and blood, heart, brain, and one leg were obtained for T. gondii examination. Antibodies to T. gondii were found in sera of all chickens with titers of 1:40 in one, 1:320 in three, and 1:640 or higher in seven chickens tested by the modified agglutination test (MAT). The goose had a MAT titer of 1:320. For isolation of T. gondii, whole heart and brain and 50g of leg muscles were digested in an acid-pepsin solution and bioassayed in four mice for each tissue. Viable T. gondii was isolated from tissues of all 11 chickens and the goose. Genotyping of these 12 T. gondii isolates using polymorphism at the genetic loci SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, a new SAG2 and Apico revealed that all isolates had Type II alleles at all loci, indicating these T. gondii isolates belong to the predominant clonal Type II lineages. This is the first report of isolation of viable T. gondii from a domestic goose (Anser anser).