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Morphological and genetic characterization of the first Isospora species (I. lugensae n. sp.) from a Kerguelen petrel (Lugensa brevirostris)

Yang, R.ORCID: 0000-0003-2563-2015, Brice, B., Liu, Q., Berto, B.P., Austen, J.ORCID: 0000-0002-1826-1634 and Ryan, U.M.ORCID: 0000-0003-2710-9324 (2021) Morphological and genetic characterization of the first Isospora species (I. lugensae n. sp.) from a Kerguelen petrel (Lugensa brevirostris). Parasitology Research .

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A new coccidian species, Isospora lugensae n. sp., was described from a single Kerguelen petrel (Lugensa brevirostris). Sporulated oocysts (n = 25) were characterized as subspheroidal to ellipsoidal measuring 24–25 μm × 21–23 μm (24.8 × 22.2 μm) in length/width (L/W), respectively, with a ratio of 1.07–1.14 μm (1.12). They contained a bi-layered wall with a thickness of 0.8–1.2 μm (1.0) and the outer layer smooth, with c.2/3 of total thickness. The oocyst contained two polar granules with both micropyle and oocyst residuum absent. Ovoidal sporocysts (n = 25) measured 15–16 μm × 10–11 μm (15.7 × 10.8 μm) in L/W, with a ratio of 1.41–1.49 μm (1.46). A flattened to knob-like Stieda body was present (c.0.5 μm deep × 2.5 μm wide) as well as a rounded to trapezoidal sub-Stieda (c.1.5 μm deep × 3.0 μm wide); however, no para-Stieda body was detected. The sporocyst residuum was composed of scattered spherules of different sizes, while vermiform sporozoites contained a refractile body, nucleus and visible striations. Analysis of the full-length mitochrondrial (mtDNA) genome revealed 3 protein-coding genes, (CytB, COI and COIII), 18 LSU and 14 small subunit (SSU) rDNA fragments, without transfer RNA genes with a total length of 6257 bp. Phylogenetic analysis of genomic SSU ribosomal sequences indicated that Isospora lugensae n. sp. is genetically similar to Eimeria reichenowi, isolated from a red-crowned crane (Grus japonensis) from Japan, with a 96.6% homology. The mtDNA sequence is most similar to Isospora serinuse with a 95.8% genetic similarity. Based on morphological and molecular data, this isolate is a new species of coccidian parasite that to date has only been found in a Kerguelen petrel.

Item Type: Journal Article
Murdoch Affiliation(s): Australian National Phenome Center
Harry Butler Institute
Health Futures Institute
Vector and Waterborne Pathogens Research Group
Publisher: Springer Verlag
Copyright: © 2021 Springer Nature Switzerland AG.
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