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)

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 3 chickens donated all I I remaining chickens and a goose on his property for the present study. All I I chickens and a goose were euthanized, and blood, heart, brain, and 1 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 50 9 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 11 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). Published by Elsevier B.V.