Formation of the cyst wall in the process of cystoformation in sarcosporidian sarcocystis dispersa

Abstract

A new Eimeria species is described from a red-capped parrot (Purpureicephalus spurius). Sporulated oocysts (n = 31) were spherical to subspherical, with a rough bilayered oocyst wall 0.8 μm thick. Oocysts measured 24.0 × 22.8 (20.4–26.4 × 18.3–25.9) μm, oocyst length/width ratio, 1.10. Oocyst residuum, polar granule and micropyle were absent. Sporocysts are elongate-ovoid, 11.0 × 7.3 (12.7–9.2 × 7.9–6.6) μm, sporocyst length/width ratio, 1.51 (1.33–1.71). The thin convex Stieda body and indistinct substieda bodies were present and the sporocyst residuum was composed of numerous small granules less than 1.0 μm in diameter dispersed randomly. Each sporocyst contained 2 sausage-shaped sporozoites in head-to-tail arrangement. The sporozoite nuclei were located centrally surrounded by refractile bodies. Molecular analysis was conducted at two loci; the 18S ribosomal RNA gene and the cytochrome c oxidase subunit I gene. At the18S locus, the new isolate shared 99.0% genetic similarity with Eimeria dispersa and Eimeria innocua from the turkey. At the cytochrome c oxidase subunit I gene locus, this new isolate was most closely related to E. dispersa and E. innocua, presented 99.0% and 98.0% genetic similarity, respectively. This new isolate and E. dispersa grouped together in the same clade. Based on the morphological and molecular data, this isolate is a new species of coccidian parasite, which is named Eimeria purpureicephali n. sp. after its host, the red-capped parrot (Purpureicephalus spurius).