ABSTRACT
PURPOSE: Members of the genus Isospora commonly infect a wide variety of wild birds. By combining morphometric and genetic data, we are able to differentiate and describe a new apicomplexan parasite, Isospora picoflavae n. sp., from the Northern Yellow-shafted Flicker (Colaptes auratus luteus) in Ontario, Canada. METHODS: Unsporulated oocysts were observed in intestinal contents obtained during necropsy; these oocysts completed exogenous sporulation within 7 days at room temperature. Complete nuclear 18S rDNA and complete mitochondrial genome sequences were obtained from this previously undescribed Isospora sp. to compare with related coccidia. RESULTS: Sporulated oocysts were subspherical in shape measuring an average of 22.7 × 21.7 µm (n = 53; mean shape index 1.05) containing a near-spherical polar granule. Sporocysts were ovoidal to ellipsoidal in shape, measuring an average size of 17.0 × 10.5 µm (n = 9; mean shape index 1.62). Sporocyst residuum was concentrated in an irregular, spherical mass in the middle of each sporocyst. The isolated oocysts differed morphologically from other Isospora species reported to infect members of the family Picidae. Based on phylogenetic analyses using either combined nuclear 18S rDNA and mitochondrial cytochrome c oxidase I (COI) sequences or complete mitochondrial genome sequences, this Isospora sp. n. isolated from the Northern Flicker grouped within a clade containing Isospora species described from various passeriform hosts. CONCLUSION: Based on combined morphological and molecular data, the oocysts found in the gastrointestinal contents of Colaptes auratus luteus represent a new species of Isospora named herein as Isospora picoflavae n. sp.
Subject(s)
Bird Diseases , Isospora , Isosporiasis , Passeriformes , Animals , Bird Diseases/parasitology , DNA, Ribosomal/genetics , Electron Transport Complex IV/genetics , Feces/parasitology , Isosporiasis/parasitology , Ontario , Oocysts , Passeriformes/parasitology , Phylogeny , RNA, Ribosomal, 18S/genetics , RNA, Ribosomal, 28S/geneticsABSTRACT
The complete mitochondrial genome of Eimeria leuckarti (Eimeriidae, Coccidia, Apicomplexa) was obtained. This morphologically distinctive coccidium is considered to be the only valid Eimeria species of equids and it infects a range of both domestic and wild horses and their relatives. Despite the distinctive appearance of the oocysts of E. leuckarti, the mitochondrial genome organization and gene contents were comparable to other Eimeria spp. and related eimeriid coccidia infecting a range of mammals and birds. The greatly reduced 6242 bp genome is circular-mapping and contains three protein-coding genes (COI, COIII, CytB), 18 fragments encoding the large subunit rRNA (LSU), and 13 fragments encoding the small subunit (SSU) rRNA. No tRNA was encoded similar to other Apicomplexa. A Bayesian inference tree based on aligned CDS and rDNA fragments from Eimeria leuckarti and 34 other coccidia demonstrated that this mt genome has close phylogenetic affinities to Eimeria and Isospora species, and related eimeriid coccidia.