Morphological and molecular characterization of Eimeria haematodi, coccidian parasite (Apicomplexa: Eimeriidae) in a rainbow lorikeet (Trichoglossus haematodus)

Vitamin B12 deficiency in newly weaned goat kids associated with clinical infection with Eimeria arloingi

A severe outbreak of diarrhea associated with poor growth was reported in ten newly weaned goat kids that originated from a research farm (Group A). Two of these kids underwent necropsy examination. Five goat kids of the same age maintained in the same pen showed no clinical signs (Group B). The clinical, gross pathological and histopathological features of the clinically sick animals were consistent with severe coccidiosis. Group A animals had significantly lower levels of serum vitamin B12 (<200 pg/ml) compared with group B animals (2000 pg/ml). In addition, kids belonging to group A had significantly higher Eimeria arloingi oocysts per gram (OPG) of faeces (101,400/g) compared with kids of group B (9,154/g). Microscopy and molecular tools (18S rRNA and COI genes) confirmed that the goat kids were infected with the caprine protozoan parasite E. arloingi. This study provides a definitive association between low levels of serum vitamin B12 and clinical E. arloingi infection, and also provides support to our previous studies that demonstrated how low levels of serum vitamin B12 leads to an impairment of neutrophil function and thereby potential lowered immunity to pathogens.

Detection and quantification of house mouse Eimeria at the species level - Challenges and solutions for the assessment of coccidia in wildlife

Detection and quantification of coccidia in studies of wildlife can be challenging. Therefore, prevalence of coccidia is often not assessed at the parasite species level in non-livestock animals. Parasite species – specific prevalences are especially important when studying evolutionary questions in wild populations. We tested whether increased host population density increases prevalence of individual Eimeria species at the farm level, as predicted by epidemiological theory.

We studied free-living commensal populations of the house mouse (Mus musculus) in Germany, and established a strategy to detect and quantify Eimeria infections. We show that a novel diagnostic primer targeting the apicoplast genome (Ap5) and coprological assessment after flotation provide complementary detection results increasing sensitivity. Genotyping PCRs confirm detection in a subset of samples and cross-validation of different PCR markers does not indicate bias towards a particular parasite species in genotyping. We were able to detect double infections and to determine the preferred niche of each parasite species along the distal-proximal axis of the intestine. Parasite genotyping from tissue samples provides additional indication for the absence of species bias in genotyping amplifications. Three Eimeria species were found infecting house mice at different prevalences: Eimeria ferrisi (16.7%; 95% CI 13.2–20.7), E. falciformis (4.2%; 95% CI 2.6–6.8) and E. vermiformis (1.9%; 95% CI 0.9–3.8). We also find that mice in dense populations are more likely to be infected with E. falciformis and E. ferrisi.

We provide methods for the assessment of prevalences of coccidia at the species level in rodent systems. We show and discuss how such data can help to test hypotheses in ecology, evolution and epidemiology on a species level.

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Flotation and PCR provide complementary results for Eimeria detection in house mice.

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Genotyping PCRs confirm detections.

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E. ferrisi, E. falciformis, and E. vermiformis infect natural populations of M. musculus.

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Double infections and preferentially infected tissues could be identified using qPCR.

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Potential virulence prevalence trade-off for Eimeria of house mice.

Morphological and molecular characterization of three Eimeria species from captured rangeland goats in Western Australia

Faecal shedding of Eimeria by captured rangeland goats (Capra hircus) was investigated using a longitudinal observational study. Faecal samples were collected from 125 male goats on four occasions. The first sampling occurred following capture and transport, immediately after arrival at a commercial goat depot (feedlot) in Western Australia, with subsequent 3 sample collections occurring at one month intervals thereafter. Goats were composite breed and aged approximately 9-12months on arrival at the feedlot. Prevalence and shedding intensity (faecal oocyst concentration) for Eimeria were determined using qPCR. Species were identified from individual oocysts (isolated using micromanipulation) using molecular analysis at two loci, specifically 18S rRNA and mitochondrial cytochrome oxidase gene (COI), and confirmed by microscopy. Longitudinal prevalence (animals positive at least once) for Eimeria spp. by qPCR was 90.4%, with 60% goats shedding Eimeria spp. on more than one occasion. Point prevalence (prevalence at a single sampling occasion) ranged from 2.4% (fourth sampling) to 70.4% (second sampling). Three species were identified at the 18S rRNA locus and confirmed by microscopy: E. christenseni (longitudinal prevalence for single infection 34.4%), E. hirci (17.6%) and E. arloingi (8.8%) over the four sample collections. Mixed infections were identified in 56.8% goats (longitudinal prevalence). 18S rRNA sequences from E. christenseni and E. hirci were 100% homologous with ovine E. ahsata and E. crandallis respectively, and E. arloingi was 100% similar to caprine E. arloingi. At the COI locus, E. christenseni, E. hirci and E. arloingi grouped separately, and were closely related to ovine E. ahsata, with genetic similarities of 96.5%, 92.6% and 91.4% respectively. This is the first report for molecular characteristics of caprine-derived Eimeria spp. using a combination of 18S rRNA and COI. Molecular techniques can be used to identify Eimeria spp. in goat faecal samples, specifically through characterization at 18S locus and other gene loci when used in parallel. Molecular techniques offer some advantages over microscopy for identification of Eimeria species, particularly with respect to precision.

Morphological and molecular characterization of Eimeria purpureicephali n. sp. (Apicomplexa:Eimeriidae) in a red-capped parrot (Purpureicephalus spurius, Kuhl, 1820) in Western Australia

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).

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A new Eimeria species (E. purpureicephali n. sp.) in a red-capped parrot.

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Morphology study: distinct to other validated Eimeria species.

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Genetic study: 99% similarity with E. dispersa at 18S and COI loci.