ORIGINAL PAPER Toxoplasmosis in geese and detection of two new atypical Toxoplasma gondii strains from naturally infected Canada geese (Branta canadensis) Shiv Kumar Verma 1 & Rafael Calero-Bernal 1 & Camila K. Cerqueira-Cézar 1 & Oliver C. H. Kwok 1 & Mike Dudley 2 & Tiantian Jiang 3 & Chunlei Su 3 & Dolores Hill 1 & Jitender P. Dubey 1 Received: 10 November 2015 /Accepted: 8 January 2016 /Published online: 21 January 2016 # Springer-Verlag Berlin Heidelberg (outside the USA) 2016 Abstract Wild birds are important in the epidemiology of toxoplasmosis because they can serve as reservoir hosts, and vectors of zoonotic pathogens including Toxoplasma gondii. Canada goose (Branta canadensis) is the most widespread geese in North America. Little is known concerning T. gondii infection in both migratory, and local resident pop- ulations of Canada geese. Here, we evaluated the seropreva- lence, isolation, and genetic characterization of viable T. gondii isolates from a migratory population of Canada geese. Antibodies against T. gondii were detected in 12 of 169 Canada geese using the modified agglutination test (MAT, cutoff 1:25). The hearts of 12 seropositive geese were bioassayed in mice for isolation of T. gondii. Viable parasites were isolated from eight. One isolate was obtained from a seropositive goose by both bioassays in mice, and in a cat; the cat fed infected heart excreted T. gondii oocysts. Additionally, one isolate was obtained from a pool of four seronegative (<1:25) geese by bioassay in a cat. The T. gondii isolates were further propagated in cell culture, and DNA extracted from cell culture-derived tachyzoites were charac- terized using 10 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genetic markers (SAG1, 5′ and 3′SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). The results revealed five different genotypes. ToxoDB PCR-RFLP genotype #1 (type II) in one isolate, genotype #2 (type III) in four isolates, genotype #4 in two isolates, and two new genotypes (ToxoDB PCR-RFLP genotype #266 in one isolate and #267 in one isolate) were identified. These results indicate genetic diversi- ty of T. gondii strains in the Canada geese, and this migratory bird might provide a mechanism of T. gondii transmission at great distances from where an infection was acquired. Keywords Canada geese . Toxoplasma gondii . Bioassay . Genotype Introduction The protozoan Toxoplasma gondii infects virtually all warm- blooded animals, including birds, humans, livestock, and ma- rine mammals (Dubey 2010). The consumption of raw or undercooked meat infected with T. gondii is considered an important source of infection in humans (Dubey 2010). Canada goose (Branta canadensis), the most widespread goose in North America, is found in every contiguous US states and Canadian provinces at one time of the year or an- other. Their populations increased 4.5 folds from 1.26 million in 1970 to 5.69 million in 2012 (Dolbeer et al. 2014). Canada geese are wild, hunted for their meat for human consumption. Geese can serve as a reservoir host and vector host of T. gondii to infect the other hosts, and the new ecosystems along the flyway. Little is known of T. gondii infection in Canada geese. Here, we report the serology, isolation, and genetic character- ization of T. gondii from Canada geese. Additionally, we * Jitender P. Dubey Jitender.Dubey@ars.usda.gov 1 United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA 2 United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Farm Services, Building 513, Beltsville, MD 20705-2350, USA 3 Department of Microbiology, University of Tennessee, Knoxville, TN 37996-0845, USA Parasitol Res (2016) 115:1767–1772 DOI 10.1007/s00436-016-4914-8