Morphological and molecular characterization of Isospora neochmiae n. sp. in a captive-bred red-browed finch (Neochmia temporalis) (Latham, 1802)

Morphological and molecular characterization of Eimeria haematopusi n. sp. (Apicomplexa: Eimeriidae) in an Australian Pied Oystercatcher (Haematopus longirostris) (Aves: Charadriiformes)

A novel Eimeria Schneider, 1875 species is described from an Australian pied oystercatcher Haematopus longirostris Vieillot, in Western Australia. The pied oystercatcher was admitted to the Kanyana Wildlife Rehabilitation Centre (KWRC), Perth, Western Australia in a poor body condition, abrasion to its right hock and signs of partial delamination to its lower beak. Investigation into potential medical causes resulted in a faecal sample being collected and screened for gastrointestinal parasites. Unsporulated coccidian oocysts were initially observed in the faeces and identified as Eimeria upon sporulation. The sporulated oocysts (n = 20) are ellipsoidal, 20-21 × 12-13 μm in shape and have thick bi-layered walls which are c.2/3 of the total thickness. Micropyle is present, robust and protruding, and occasionally has a rounded polar body attached to the micropyle. Within the oocyst, a residuum, in addition, two to five polar granules are present. There are four ellipsoidal sporocysts 9-11 × 5-6 μm with flattened to half-moon shaped Stieda bodies. Sub-Stieda body and para-Stieda body are absent. The sporocysts contain sporocyst residuums composed of a few spherules scattered among the sporozoites. Within the sporozoites, anterior and posterior refractile bodies are present, but the nucleus is indiscernible. To further characterise the novel Eimeria species from H. longirostris, molecular analysis was conducted at the 18S ribosomal RNA locus, using PCR amplification and cloning. Two cloned sequences from the novel Eimeria were compared with those from other Eimeria spp. with the highest genetic similarity of 97.6% and 97.2% from Clone 1 and 2, respectively with Eimeria reichenowi (AB544308) from a hooded crane (Grus monacha Temminck) in Japan. Both sequences grouped in a clade with the Eimeria spp. isolated from wetland birds, which include Eimeria paludosa (KJ767187) from a dusky moorhen (Gallinula tenebrosa Gould) in Western Australia, Eimeria reichenowi (AB544308) and Eimeria gruis (AB544336) both from hooded cranes. Based on the morphological and molecular data, this Eimeria sp. is a new species of coccidian parasite and is named Eimeria haematopusi n. sp. after its host H. longirostris.

Identification and genetic characterization of a novel species of Choleoeimeria Schneider, 1875 from a captive-bred bilby (Thylacomyidae; Macrotis lagotis) (Reid, 1837) in Western Australia

A novel Eimeria sp. from a captive-bred bilby (Macrotis lagotis Reid, 1837) has been identified in Western Australia. The bilby was bred at the Kanyana Wildlife Rehabilitation Centre, Perth, as part of the National Bilby Recovery Plan. Oocysts (n = 31) irregular blunt ellipsoidal, 17-18 × 11-12 (17.2 × 11.3); length/width (L/W) ratio 1.4-1.5 (1.5). Wall bi-layered, 0.8-1.0 (0.9) thick, outer layer smooth, c.2/3 of total thickness. Micropyle barely discernible. Oocyst residuum is absent, but 2-3 small polar granules are present. Sporocysts (n = 31) ovoidal, 7-8 × 5-6 (7.8 × 5.7); L/W ratio 1.3-1.4 (1.4). Stieda, sub-Stieda and para-Stieda bodies absent or indiscernible; sporocyst residuum present, usually as an irregular body consisting of numerous granules that appear to be membrane-bound or sometimes diffuse among sporozoites. Sporozoites vermiform with a robust refractile body. Further molecular characterization was conducted on the sporulated oocysts. At the 18S locus, it sat in a large clade of the phylogenetic tree with two isolates of Eimeria angustus from quendas (Isoodon obesulus Shaw, 1797) and the Choleoeimeria spp. It shared the highest identity with E. angustus (KU248093) at 98.84%; at the COI gene locus, it was unique and most closely related to Choleoeimeria taggarti, which is hosted by another species of marsupial, the yellow-footed antechinus (Antechinus flavipes flavipes), with 90.58% genetic similarity. Based on morphological and molecular data, this isolate is a new species and named as Choleoeimeria yangi n. sp.

Morphological and molecular characterization of Isospora elliotae n. sp. (Apicomplexa: Eimeriidae) from the Australian magpie Gymnorhina tibicen (Latham, 1801) (Passeriformes: Artamidae) in Western Australia

A new coccidian species, Isospora elliotae n. sp., from the Australian magpie Gymnorhina tibicen (Latham, 1801) in Western Australia, is described and characterized morphologically and molecularly. Microscopic analysis of a faecal sample identified subspheroidal oocysts (n = 20), 20-22 × 18-20 (20.7 × 18.7); length/width (L/W) ratio 1.05-1.14 (1.10). Wall bi-layered, 1.0-1.3 (1.2) thick, outer layer smooth, c. 2/3 of total thickness. Micropyle and oocyst residuum absent, but usually two polar granules are present. Sporocysts (n = 28) ovoidal, 12-13 × 9-11 (12.6 × 9.7); L/W ratio 1.22-1.35 (1.30). Stieda body present, flattened to half-moon-shaped, c. 0.5 deep × 2.0 wide; sub-Stieda indistinct or barely discernible, c. 1.0 deep × 2.5 wide; para-Stieda body absent; sporocyst residuum present, composed of granules dispersed among the sporozoites. Sporozoites vermiform, with anterior and posterior refractile bodies and nucleus. Segments of three gene loci (18S rRNA, 28S rRNA and COI) were sequenced and I. elliotae n. sp. exhibited 99.8% genetic similarity to Isospora sp. MAH-2013a (KF648870) followed by 99.7% genetic similarity to Isospora neochmiae (Yang, Brice & Ryan, 2016) (KT224380) at the 18S rRNA gene locus. It shared 97.0% genetic similarity with an unnamed Isospora sp. (AY283852) at the 28S rRNA gene locus and it also shared the highest genetic similarity of 99.8% with the unnamed Isospora sp. from an American crow (OL999120) at the COI gene locus. Based on morphological and molecular data, this isolate is a new species named as I. elliotae n. sp.

Severe deforming dermatitis in a kitten caused by Caryospora bigenetica

Background

Caryospora bigenetica is an intracellular protozoan parasite, which in its primary hosts, typically snakes, is found it the intestine. Extraintestinal multiplication with the development of tissue cysts takes place in secondary hosts, which are normally prey for snakes. Natural infection in domestic animals has been reported only in dogs; this is the first report of C. bigenetica infection in a cat.

Case presentation

A stray kitten developed nodular dermatitis after being adopted by a shelter. Firm swelling, nodules, and crusts were present mainly on the nasal bridge, eyelids, and pinnae. Histopathology and cytology revealed severe pyogranulomatous inflammation with abundant intracellular organisms suggestive of apicomplexan protozoa. Treatment with clindamycin 13 mg/kg twice daily was initiated, but the cat was euthanized because of the worsening condition. Transmission electron microscopy confirmed parasite’s apicomplexan origin postmortem, and the causative agent was identified as C. bigenetica by polymerase chain reaction and DNA sequencing.

Conclusions

We present the first case of a naturally occurring infection with C. bigenetica in a cat. Although the definitive etiological diagnosis relied on molecular identification, the abundance of unsporulated oocysts and caryocysts and the parasite's effective reproduction within macrophages and in several other cell types might have enabled differentiation from other protozoal infections and allowed a presumptive diagnosis through cytology and histopathology.

Morphological and molecular characterization of a new species of Isospora Schneider, 1881 (Apicomplexa: Eimeriidae) from the western wattlebird Anthochaera lunulata Gould in Western Australia

A new coccidian species, Isospora lunulatae n. sp., from the western wattlebird Anthochaera lunulata Gould in Western Australia is described and characterised molecularly. Microscopic analysis of a faecal sample identified subspheroidal oöcysts measuring 27-34 × 26-31 (30.6 × 29.4) μm (n = 20), with a length/width (L/W) ratio of 1.0-1.1 (1.0). Oöcysts have a bi-layered wall, 0.9-1.2 (1.0) μm thick; the outer layer is smooth, representing c.2/3 of total thickness. Micropyle and oöcyst residuum are both absent, but a polar granule is present. Sporocysts are ovoidal, 17-19 × 10-12 (18.3 × 10.7) μm, with a L/W ratio of 1.6-1.8 (1.7) and occupying about 21% of the area (each one) within the oöcyst. Stieda body is flattened to rounded, measuring on average 0.9 × 1.8 μm; sub-Stieda body is rounded to rectangular, measuring on average 1.5 × 2.6 μm; para-Stieda body is absent. Sporocyst residuum has an irregular shape consisting of numerous granules and appears membrane-bound. Sporozoites are vermiform 12.8 × 3.0 μm on average, with prominent striations at the more pointed end and two refractile bodies below striations. Segments of three gene loci (18S rRNA, 28S rRNA and cox1) were sequenced and I. lunulatae n. sp. exhibited 99.6% genetic similarity to Isospora phylidonyrisae Yang, Brice, Berto & Ryan, 2021 at the 18S rRNA gene locus, 99.8% genetic similarity to Isospora anthochaerae Yang, Brice & Ryan, 2014 and shared a 98.1% genetic similarity with Isospora manorinae Yang, Brice, Jian & Ryan, 2016 at the cox1 gene locus. Morphological and molecular data support the distinct species status of the new species.

Morphological and molecular description of a new species of Isospora (Apicomplexa) from a New Holland honeyeater (Phylidonyris novaehollandiae)

A new Isospora species is described from New Holland honeyeaters (Phylidonyris novaehollandiae). Sporulated oocysts (n = 25) were characterised as subspheroidal, 29-32 × 28-31 (29.8 × 29.4); length/width (L/W) ratio 1.01-1.02 (1.01). Wall bi-layered, 1.3-1.6 (1.5) thick, outer layer smooth, c.2/3 of total thickness. Micropyle and oocyst residuum absent, but usually two polar granules are present. Sporocysts (n = 25) ovoidal, 18-19 × 12-14 (18.4 × 12.3); L/W ratio 1.42-1.53 (1.50). Stieda body present, flattened, c.0.5 deep × 2.5 wide; sub-Stieda present, rounded, c.2.5 deep × 3.5 wide; para-Stieda body absent; sporocyst residuum present, usually a distinctly irregular body consisting of numerous small granules that appear to be membrane-bound. Sporozoites vermiform, with robust anterior and posterior refractile bodies. Molecular characterization was conducted at the 18S and 28S ribosomal RNA and the mitochondrial (mt) cytochrome oxidase (COI) loci. Phylogenetic analysis of genomic 18S and mt COI sequences indicated that Isospora phylidonyrisae n. sp. was genetically similar to Isospora coronoideae, isolated from an Australian raven (Corvus coronoides) in Western Australia, with a 99.3% and 98.4% homology, respectively. The 28S rRNA sequence was most similar to Isospora anthochaerae (KF766053) and Isospora manorinae (KT224381), both with a 98.2% genetic similarity. Based on morphological and genetic data, this isolate is a new species of Isospora, which is named Isospora phylidonyrisae n. sp. after its host.

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

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.

Detection and characterization of the Isospora lunaris infection from different finch hosts in southern Iran

This study was conducted to investigate the Isosporoid protozoan infections in finch types. Fecal samples were collected from marketed domestic Java sparrows (Lonchura oryzivora), colored and white Zebra finch (Taeniopygia guttata), and European goldfinch (Carduelis carduelis) in southern Iran. The coccidial oocysts were recovered and investigated according to the morphological features and the ribosomal gene markers. Additionally, a challenge infection was conducted with 5 × 10⁴ and 5 × 10³ sporulated oocysts in four java sparrows to estimate the clinical manifestations. Based on the morphology, the oocysts of Isospora lunaris were identified in all sampled bird types; however, the molecular method revealed the isolates had considerable similarities with some of Isospora and systemic Isospora-like organisms named as Atoxoplasma. Phylogenetic data also constructed an Atoxoplasma/Isospora clade with high sequence identities. High dose of the challenge with the parasite led to severe depression and sudden death, but it did not coincide with remarkable lesions and parasitic invasion in visceral organs. Contrary to molecular results, this feature is consistent with the common Isospora infections in passerines and differs from those described for Atoxoplasma species. Because of the prevalence, possibility of transmission, and clinical consequences, preventive measures are necessary to avoid outbreaks of isosporoid infections among finch type birds.

Morphological and molecular characterization of Cystoisospora laidlawi oocysts (Apicomplexa: Eimeriidae) in farmed American mink (Neovison vison) in Denmark

From a longitudinal survey conducted on 30 Danish mink farms in 2016, 11.0% of faecal samples (456/4140) were positive for Cystoisospora laidlawi oocysts by microscopy, with 60% (189/315) of mink being positive at least once during the study period. Morphological analysis of sporulated oocysts identified Cystoisospora oocysts measuring 34.3 × 29.5 μm with an oocyst length/width (L/W) ratio of 1.2. The morphological features of the oocysts were identical to Isospora laidlawi previously morphological identified in farmed mink from Denmark and elsewhere. Phylogenetic analysis of 18S rDNA sequences (1221 bp) from three positive mink indicated that Cystoisospora from mink shared the highest genetic similarity to C. canis from a Canadian dog (99.6%). The phylogenetic analysis placed Cystoisospora from mink in a clade with other Cystoisospora isolates.

Molecular and morphological analysis of a Caryospora-like isolate (Apicomplexa: Eimeriidae) from the magpie-lark (Grallina cyanoleuca) (Latham, 1801) in Western Australia

A new Caryospora-like isolate is described from a magpie-lark (Grallina cyanoleuca) in Western Australia. Sporulated oocysts of the Caryospora-like isolate (n = 35) are subspherical with a shape index of 1.13 ((21.5 (19.7-23.6) × 19.0 (18.1-19.8) μm). The bilayered oocyst wall is smooth. Micropyle, polar granule and oocyst residuum are absent. The sporocyst is ellipsoidal, 18.9 (17.2-20.8) × 12.3 (11.9-12.8) μm, with a shape index (length/width) of 1.54. The sporocyst wall is bilayered. Stieda and substieda bodies are present, the Stieda body is small and flattened and the substieda is trapezoidal. Sporocyst with eight sporozoites arranged head to tail. The sporozoites are vermiform, 18.9 (17.2-20.8) × 12.3 (11.9-12.8) μm and have striations at the anterior end. Each sporozoite has both anterior and posterior refractile bodies. A sporocyst residuum is present. Molecular characterization of the isolated Caryospora-like oocysts was conducted at the 18S ribosomal RNA and the mitochondrial cytochrome oxidase (COI) loci. At the 18S rRNA locus, the Caryospora-like isolate exhibited 88.8% to 96.5% similarity with other Caryospora spp. from different hosts. At the COI locus, it showed 91.5% similarity to Caryospora cf. bigenetica JB-2013 (KF859856) from the rattlesnake, Sistrurus catenatus.

Isospora coronoideae n. sp. (Apicomplexa: Eimeriidae) from the Australian raven (Corvus coronoides) (Passeriformes: Corvidae) (Linnaeus, 1758) in Western Australia

A new Isospora (Apicomplexa: Eimeriidae) species is described from an Australian raven (Corvus coronoides) in Western Australia. Sporulated oocysts (n = 21) are ovoid, 21.2 (18.4-23.9) μm in length and 18.8 (16.9-20.6) μm in width, with a shape index of 1.13. The bi-layered oocyst wall is smooth and colourless, 1.2 μm thick. A polar granule and oocyst residuum is present, but the micropyle is absent. The sporocysts are ovoid-shaped, 16.3 (13.7-18.9) × 10.7 (8.4-12.9) μm, with a shape index (length/width) of 1.52. Stieda and substieda bodies are present, the Stieda body being small and hemidome-shaped and the substieda being indistinct. Each sporocyst with four vermiform sporozoites arranged head to tail. The sporozoites are crescent-shaped, 9.0 (8.9-9.2) × 2.7 (2.3-3.0) μm, with a shape index (length/width) of 3.33. The sporocyst residuum is present. The isolated oocysts had different morphological characteristics when compared with all known Isospora spp. The coccidian parasite was analysed at the 18S and 28S ribosomal RNA and the mitochondrial cytochrome oxidase (COI) loci. At the 18S locus, I. coronoideae n. sp. exhibited 98.9% similarity to I. neochmiae from a captive-bred red-browed finch (KT224380) and Isospora sp. from domestic pigeons (Columba livia domestica) (AB757860), 98.5% similarity to I. gryphoni (AF080613) from an American goldfinch and 98.3% similarity to I. manorinae (KT224379) from a yellow-throated miner. At the 28S locus, it exhibited 95.4% and 94.8% similarity to I. manorinae (KT224381) and I. anthochaerae (KF766053), respectively. At the COI locus, it exhibited 99.8% and 99.7% similarity to I. butcherae (KY801687) and I. neochmiae (KT224378), respectively. Based on morphological and molecular data, this isolate is a new species of Isospora, which is named Isospora coronoideae n. sp. after its host, the Australian raven (Corvus coronoides) (Passeriformes: Corvidae) (Linnaeus, 1758).