title: A new Isospora sp. from Carduelis tristis (Aves: Fringillidae) from Ontario, Canada.
abstract: Isospora gryphoni n. sp. is described from oocysts found in the feces of the American goldfinch, Carduelis tristis, from Guelph, Ontario, Canada. The oocysts are spherical to subspherical, with a double-layered, smooth, colorless oocyst wall, 29.2 x 30.7 microm (25-33 x 28-34; n = 30) with 2-4 rice-grain-shaped polar bodies; no micropyle or residuum. Sporocysts are ovoid, 22.2 x 13.4 microm (15-25 x 12-14.5; n = 30) with a small Stieda body, indistinct substiedal body, and prominent sporocyst residuum. Sporozoites are vermiform, each with a large refractile body at the posterior end. Forty-nine of 52 (94%) wild-caught adult C. tristis and 1 juvenile bird (minimum 12 days old) were excreting oocysts of I. gryphoni. None of 36 nestlings (maximum 10 days old) was excreting oocysts. Fecal encrustations from 7 of 10 used nests were found to contain oocysts of I. gryphoni.
authors.affiliation: Department of Zoology, University of Guelph, Ontario, Canada.
authors.forename: V A
authors.initials: VA
authors.lastname: Olson
authors.forename: G J
authors.initials: GJ
authors.lastname: Gissing
authors.forename: J R
authors.initials: JR
authors.lastname: Barta
authors.forename: A L
authors.initials: AL
authors.lastname: Middleton
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology / Q000469:parasitology*; D001717:Birds; D003048:Coccidiosis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D005243:Feces / Q000469:parasitology; D007549:Isospora / Q000145:classification* / Q000648:ultrastructure; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence