Morphological and molecular characterization of a novel eimerian species (Apicomplexa: Eimeriidae) from the Australian pelican Pelecanus conspicillatus Temminck, 1824 (Pelecaniformes: Pelecanidae) in Western Australia

• Published in: Parasitology international Vol. 96; p. 102756
• Main Authors: Yang, Rongchang, Austen, Jill M., Elloit, Aileen, Gao, Huimin, Berto, Bruno P.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-10-2023
• Subjects: 18S rRNA gene; 28S rRNA gene and COI gene; Animals; Australia - epidemiology; Australian pelican; Bird Diseases - epidemiology; Bird Diseases - parasitology; Birds; coccidia; Ducks; Eimeria; Eimeria - genetics; Electron Transport Complex IV - genetics; Feces - parasitology; Oocysts; Phylogeny; RNA, Ribosomal, 18S - genetics; Sporozoites; Western Australia - epidemiology; Australia; Western Australia; 28S rRNA gene and COI gene; coccidia; Australian pelican; Eimeria; 18S rRNA gene
• ISSN: 1383-5769; 1873-0329
• DOI: 10.1016/j.parint.2023.102756

A new Eimeria Schneider, 1875 species is described from an Australian pelican Pelecanus conspicillatus Temminck, 1824 in Western Australia. Sporulated oocysts (n = 23) subspheroidal, 33–35 × 31–33 (34.1 × 32.0) μm; length/width (L/W) ratio 1.0–1.1 (1.07). Wall bi-layered, 1.2–1.5 (1.4) μm thick, outer layer smooth, c.2/3 of total thickness. Micropyle absent, but 2 or 3 polar granules surrounded by a thin membrane, apparently residual, are present. Sporocysts (n = 23) elongate ellipsoidal or capsule shaped, 19–20 × 5–6 (19.5 × 5.6) μm; L/W ratio 3.4–3.8 (3.51). Stieda body vestigial and barely discernible, 0.5 × 1.0 μm; sub-Stieda and para-Stieda bodies absent; sporocyst residuum present, composed of a few dense spherules dispersed among the sporozoites. Sporozoites with robust anterior and posterior refractile bodies and centrally located nucleus. Molecular analysis was conducted at three loci; the 18S and 28S ribosomal RNA genes and the cytochrome c oxidase subunit I (COI) gene. At the 18S locus, the new isolate shared 98.6% genetic similarity with Eimeria fulva Farr, 1953 (KP789172), which was identified from a goose in China. At the 28S locus, the new isolate shared the highest similarity of 96.2% with Eimeria hermani Farr, 1953 (MW775031) identified from a whooper-swan (Cygnus cygnus (Linnaeus, 1758)) in China. At the COI gene locus, this new isolate was most closely related to Isospora sp. isolate COI-178 and Eimeria tiliquae [25,26], presented 96.5% and 96.2% genetic similarity, respectively. Based on the morphological and molecular data, this isolate is a new species of coccidian parasite, which is named Eimeria briceae n. sp.
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•Description of E. briceae n. sp. in an Australian pelican.•Morphology: unique.•Genetic: 98.6% similar to E. fulva Farr at 18S locus.