Mixed Eimeria and Cryptosporidium infection and its effects on pathology and clinical outcomes in juvenile Asian seabass (Lates calcarifer) cultured in Thailand

Coccidiosis is an important disease in juvenile fish because of severe intestinal injury during infection. We first reported the mixed infection of intestinal coccidia and its association with health status and pathological findings in juvenile Asian seabass (Lates calcarifer) cultured in Thailand. Two groups of Asian seabass, 60-day fish and 90-day fish, were sampled to investigate prevalence and coccidian infection intensity using morphological characterization and PCR. Phylogenetic analysis of 18S rRNA gene amplified from the intestines revealed Eimeria sp. and Cryptosporidium sp. infection. The prevalence of Eimeria sp. and Cryptosporidium sp. in sampled fish was 100%. Clinical outcomes assessed, using health assessment index (HAI) scoring and semi-quantitative grading of intestinal lesions and inflammation, demonstrated that all fish developed variety of pathology and clinical illness; however, infection intensity in 60-day fish was significantly higher (p < .05) than 90-day fish. The HAI score of 60-day fish was poorer than 90-day fish, which correlated to a high infection intensity (r = .397), analysed by Pearson correlation coefficient. Overproduction of intestinal oxidants contributing to mucosal injury was examined by nitrotyrosine expression. The high production of reactive nitrogen species indicated severe inflammatory response, and intestinal injuries occurred mainly in the 60-day fish.

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.

RNA-Seq of Phenotypically Distinct Eimeria maxima Strains Reveals Coordinated and Contrasting Maturation and Shared Sporogonic Biomarkers with Eimeria acervulina

Strains of Eimeria maxima, an enteric parasite of poultry, vary in virulence. Here, we performed microscopy and RNA sequencing on oocysts of strains APU-1 (which exhibits more virulence) and APU-2. Although each underwent parallel development, APU-1 initially approached maturation more slowly. Each strain sporulated by hour 36; their gene expression diverged somewhat thereafter. Candidate biomarkers of viability included 58 genes contributing at least 1000 Transcripts Per Million throughout sporulation, such as cation-transporting ATPases and zinc finger domain-containing proteins. Many genes resemble constitutively expressed genes also important to Eimeria acervulina. Throughout sporulation, the expression of only a few genes differed between strains; these included cyclophilin A, EF-1α, and surface antigens (SAGs). Mature and immature oocysts uniquely differentially express certain genes, such as an X-Pro dipeptidyl-peptidase domain-containing protein in immature oocysts and a profilin in mature oocysts. The immature oocysts of each strain expressed more phosphoserine aminotransferase and the mature oocysts expressed more SAGs and microneme proteins. These data illuminate processes influencing sporulation in Eimeria and related genera, such as Cyclospora, and identify biological processes which may differentiate them. Drivers of development and senescence may provide tools to assess the viability of oocysts, which would greatly benefit the poultry industry and food safety applications.

Unravelling the sexual developmental biology of Cystoisospora suis, a model for comparative coccidian parasite studies

Introduction

The apicomplexan parasite Cystoisospora suis has global significance as an enteropathogen of suckling piglets. Its intricate life cycle entails a transition from an asexual phase to sexual development, ultimately leading to the formation of transmissible oocysts.

Methods

To advance our understanding of the parasite's cellular development, we complemented previous transcriptome studies by delving into the proteome profiles at five distinct time points of in vitro cultivation through LC/MS-MS analysis.

Results

A total of 1,324 proteins were identified in the in vitro developmental stages of C. suis, and 1,082 proteins were identified as significantly differentially expressed. Data are available via ProteomeXchange with identifier PXD045050. We performed BLAST, GO enrichment, and KEGG pathway analyses on the up- and downregulated proteins to elucidate correlated events in the C. suis life cycle. Our analyses revealed intriguing metabolic patterns in macromolecule metabolism, DNA- and RNA-related processes, proteins associated with sexual stages, and those involved in cell invasion, reflecting the adaptation of sexual stages to a nutrient-poor and potentially stressful extracellular environment, with a focus on enzymes involved in metabolism and energy production.

Discussion

These findings have important implications for understanding the developmental biology of C. suis as well as other, related coccidian parasites, such as Eimeria spp. and Toxoplasma gondii. They also support the role of C. suis as a new model for the comparative biology of coccidian tissue cyst stages.

Renal Coccidial Infection in North American Northern Gannets (Morus bassanus)

We identified by light microscopy micro- and macrogametes and oocysts of renal coccidia in 78 of 220 (35.5%) Northern Gannets (Morus bassanus) from the western North Atlantic population. This infection was not considered clinically significant in any of the affected birds, although the potential effect of this parasite in breeding colonies, particularly among nestlings, is unknown. Analysis of the 18S rRNA gene from frozen renal tissue by PCR and subsequent sequencing revealed 95.6% identity with Eimeria auritusi from Double-crested Cormorants (Phalacrocorax auritus), suggesting a novel Eimeria sp. in the Northern Gannets.

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.

Coccidiosis in Wild Eastern Newts (Notophthalmus viridescens): An Unexpected Finding in Consecutive Mortality Events in Tennessee, USA

Wildlife diseases are a major threat for species conservation, and there is a growing need to implement more comprehensive disease response programs to better identify these diseases of concern. During March 2017, we observed moribund and dead eastern newts, Notophthalmus viridescens, in a single pond in middle Tennessee. All moribund individuals were emaciated. We euthanized and processed all individuals immediately on-site and later performed histopathology and quantitative PCR for ranavirus, the protist Perkinsea, and chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans. One newt was positive for ranavirus. Histopathology showed no evidence of ranavirosis but did reveal overwhelming coccidiosis. Overlapping partial sequences of coccidian 18S subunit DNA showed a 96.4% match with Eimeria steinhausi, suggesting that lesions were due to a previously undescribed Eimeria sp. In 2019, two more moribund newts were encountered at the same pond. Histopathology revealed the same suspicious parasitic organisms, and one individual was positive for B. dendrobatidis. Further research on how seasonal and other environmental parameters may influence coccidia-associated morbidity and mortality is warranted. These events highlight the importance of histopathologic evaluation of mortality events and provide guidance for investigation of future outbreaks.

Interplay between Eimeria acervulina and Cryptosporidium parvum during In Vitro Infection of a Chicken Macrophage Cell Line (HD11)

BACKGROUND

Eimeria acervulina is a frequent intestinal pathogen of chickens, causing economic impact on the poultry industry. Cryptosporidium parvum is a neglected parasite in chickens. However, because of its zoonotic potential, poultry cryptosporidiosis may pose a risk to public health. Little is known about the parasite-host interactions during coinfection with both parasites. In this study, we investigated the possible interactions during in vitro coinfection of E. acervulina and C. parvum in a chicken macrophage cell line (HD11).

METHODS

HD11 cells were inoculated with E. acervulina and C. parvum sporozoites and incubated 2, 6, 12, 24, and 48 h post infection (hpi). Mono-infections for each parasite were also investigated. Real-time PCR was used to quantify parasite replication. Additionally, macrophage mRNA expression levels of IFN-γ, TNF-α, iNOS, and IL-10 were measured.

RESULTS

For both parasites, multiplication was, in most groups, lower in the coinfection group (COIG) compared with mono-infections. However, at 6 hpi, the number of C. parvum copies was higher in co-infections. Intracellular replication started to decrease from 12 hpi onward, and it was almost undetectable by 48 hpi in all groups. Infections resulted in low expression of all cytokines, except at 48 hpi.

CONCLUSIONS

Infection of avian macrophages with both E. acervulina and C. parvum seemed to hinder intracellular replication for both parasites in comparison to mono-infection. A clear reduction in intracellular parasites from 12 hpi onward details the important role potentially played by macrophages in host control of these parasites.

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

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.

Helminth-associated changes in host immune phenotype connect top-down and bottom-up interactions during co-infection

1. Within-host parasite interactions can be mediated by the host and changes in host phenotypes often serve as indicators of the presence or intensity of parasite interactions. 2. Parasites like helminths induce a range of physiological, morphological, and immunological changes in hosts that can drive bottom-up (resource-mediated) or top-down (immune-mediated) interactions with co-infecting parasites. Although top-down and bottom-up interactions are typically studied in isolation, the diverse phenotypic changes induced by parasite infection may serve as a useful tool for understanding if, and when, these processes act in concert. 3. Using an anthelmintic treatment study of African buffalo (Syncerus caffer), we tracked changes in host immunological and morphological phenotypes during helminth-coccidia co-infection to investigate their role in driving independent and combinatorial bottom-up and top-down parasite interactions. We also examined repercussions for host fitness. 4. Clearance of a blood-sucking helminth, Haemonchus, from the host gastrointestinal tract induced a systemic Th2 immune phenotype, while clearance of a tissue-feeding helminth, Cooperia, induced a systemic Th1 phenotype. Furthermore, the Haemonchus-associated systemic Th2 immune phenotype drove simultaneous top-down and bottom-up effects that increased coccidia shedding by changing the immunological and morphological landscapes of the intestine. 5. Higher coccidia shedding was associated with lower host body condition, a lower chance of pregnancy, and older age at first pregnancy, suggesting that coccidia infection imposed significant condition and reproductive costs on the host. 6. Our findings suggest that top-down and bottom-up interactions may commonly co-occur and that tracking key host phenotypes that change in response to infection can help uncover complex pathways by which parasites interact.

Intestinal Coccidian Infections in Cancer Patients: A Case Series

Introduction Coccidian protozoa and microsporidian fungi are opportunistic pathogens increasingly implicated in infections in immunosuppressed individuals. These parasites typically infect the intestinal epithelium, resulting in secretory diarrhea and malabsorption. The disease burden and timeline are both greater and longer among immunosuppressed patients. Therapeutic options for immunocompromised individuals are limited. As a result, we wanted to better characterize the disease course and treatment efficacy of these parasitic gastrointestinal infections. Methods We performed a single-center, retrospective MedMined (BD Healthsight Analytics, Birmingham, AL, USA) chart review of patients between January 2012 and June 2022 diagnosed with coccidian or microsporidian infections. Relevant data were collected from Cerner's PowerChart (Oracle Cerner, Austin, TX, USA). Descriptive analysis was performed with IBM SPSS Statistics (IBM Corp., Armonk, NY, USA), and Microsoft Excel (Microsoft, Redmond, WA, USA) was used to generate graphs and tables. Results In these 10 years, there were 17 patients with Cryptosporidium infections, four with Cyclospora infections, and no positive cultures for Cystoisospora belli or microsporidian infections. In both infections, the majority of patients experienced diarrhea, fatigue, and nausea, with vomiting, abdominal pain, appetite loss, weight loss, and fever occurring to a lesser degree. Nitazoxanide was the most common treatment for Cryptosporidium, while trimethoprim-sulfamethoxazole or ciprofloxacin were the treatments of choice for Cyclospora. Of the Cryptosporidium infections, three received combination therapy with azithromycin, immunoreconstitution, or IV immunoglobulins. Among the four Cyclospora-infected patients, one received combination therapy of ciprofloxacin and trimethoprim-sulfamethoxazole. Treatment lasted around two weeks, and 88% of Cryptosporidium patients and 75% of Cyclospora patients had a resolution of symptoms. Conclusion The most detected coccidian infection was Cryptosporidium, followed by Cyclospora, with the lack of Cystoisospora or microsporidian infections likely due to diagnostic limitations and prevalence. Cryptosporidium and Cyclospora likely caused their associated symptoms in most cases, with other possible etiologies, including graft-versus-host disease, medications, and feeding tubes. The small number of patients receiving combination therapy prohibited a comparison with monotherapy. In our patient population, though, there was a clinical response to treatment despite immunosuppression. While promising, additional randomized control experiments are required to fully understand the efficacy of parasitic treatments.

Dietary Methionine Increased the Growth Performances and Immune Function of Partridge Shank Broilers after Challenged with Coccidia

The present study investigated the effects of methionine (Met) on growth, immune function, and antioxidant capacity in partridge shank broilers, which were treated with either an anticoccidial drug or a coccidia vaccine. Chickens were fed five graded levels of Met (0.33%, 0.39%, 0.45%, 0.51%, or 0.57%) for 21 days in combination with the drug or vaccine. The results revealed that an optimal level of Met supplementation (1) increased ADFI (average daily feed intake), ADG (average daily gain), and F/G values (feed-to-gain ratio), indicating improved production; (2) increased OPG levels (oocysts per gram feces), intestinal lesion scores, bursa of Fabricius and thymus indexes, and sIgA content; (3) improved GSH-Px activities, and increased content levels of T-protein, albumin, and urea nitrogen. In addition, birds in the anticoccidial drug group had higher final weights, higher ADFI and ADG values, as well as lower F/G values, compared with birds in the vaccine group, indicating that coccidia vaccine reduces the performance of broilers. In conclusion, we found that an optimal level of dietary Met improved the production of partridge shank broilers, and this result might be related to immune function and antioxidant capacity. Optimal levels of digestible Met in terms of production performance (ADG and F/G) and immune function (sIgA in ileum mucosa) in partridge shank broilers (1-21 days) were found to be 0.418, 0.451, and 0.451 of diet, respectively, when birds were given anticoccidial drug treatment, with corresponding figures of 0.444, 0.455, and 0.452% when the coccidia vaccine was administered.

Prevalence of Gastrointestinal Nematodes, Cestodes, and Protozoans of Goats in Nyagatare District, Rwanda

Introduction

Goat farming significantly contributes to the efficient use of land and socioeconomic development in developed and developing countries. During the fiscal year 2017-2018, goats made up 13.5% of the total live livestock exported by Rwanda. Gastrointestinal parasites (GIPs) can negatively impact goat production, especially in developing countries like Rwanda. This study aimed to determine the impact of the goat' age and location (administrative cell) on the prevalence of gastrointestinal nematodes, cestodes, and protozoans (GiNCPs) of goats in Nyagatare district, Rwanda.

Methods

In this cross-sectional study, 149 faecal samples were collected from apparently unwell goats and analyzed using the simple flotation technique. Strongyle-type nematodes (STNs) infections were graded using the McMaster method. Pearson chi-square tests of independence were calculated to assess the impact of the goat' age and location on the prevalence of GiNCPs in the study area.

Results

All the goats (100%) were infected with GiNCPs. The identified types of parasites were STNs (96.0%), Coccidia (83.2%), Moniezia spp (14.8%), Strongyloides papillosus (12.8%), Nematodirus spp (0.7%) and Trichuris ovis (0.7%). Nearly 85.9% (128/149) of the goats were coinfected with 2 to 4 types of parasites and the coinfection of STNs and coccidia preponderated at 58.4%. The location (administrative cell) of the goats correlated with the prevalence of monieziasis (p<0.05). The goat's age category was also associated with the prevalence of strongyloidiasis (p<0.05).

Conclusion

All the goats (100%) were infected with GiNCPs. The location (administrative cell) of the goat also correlated with the prevalence of monieziasis. In addition, the goat's age category was associated with the prevalence of strongyloidiasis. These findings show that any control program for caprine gastrointestinal parasitoses in the study area should focus on STNs and Coccidia.

Short Communication: effect of sodium butyrate, monensin, and butyric acid on the viability of Eimeria bovis sporozoites and their degree of damage to a bovine epithelial cell line

This study aimed to determine the viability of sporozoites from Eimeria bovis when exposed to sodium butyrate (SB), monensin (MON), or butyric acid (BA), and to determine the effects of SB on sporozoite invasion of cells in comparison to MON as measured by the damage to a bovine epithelial cell line. To determine viability, isolated sporozoites were suspended in one of four treatments: control (CON) of cell culture medium alone, SB = 0.028 mg/mL suspended in control medium, MON = 0.01 mg/mL suspended in CON, and BA = 0.18 mg/mL suspended in CON. The number of live sporozoites was less for the MON and BA treatments compared to the CON and SB treatments. The number of dead sporozoites was similar regardless of treatment. There was a trend for treatment to affect the percent sporozoite viability. Control, SB and BA treatments were similar, while MON compared to control and SB had decreased percent viability. Results for MON, when compared to BA, were similar for percent viability. Lactate dehydrogenase (LDH) release was used to determine cellular damage to Madin Darby Bovine Kidney (MDBK) cells when exposed to E. bovis sporozoites in vitro. Cells were exposed to similar numbers of sporozoites and treated with: CON, SB = 0.028 mg/mL in control medium, MON = 0.01 mg/mL in control medium. Control LDH result (with sporozoites) was greater than both the SB and MON treatments while the LDH for SB and Mon and cells not exposed to sporozoites were similar. SB and MON were both shown to decrease cellular damage to MDBK cells as determined by decreased LDH release. SB has the potential to act as an anticoccidial alternative to MON.

Multilocus Sequence Typing of Eimeria maxima in Commercial Broiler Flocks

About 35% of all broiler flocks in the United States receive an anticoccidial vaccine, but it is not possible to easily differentiate Eimeria vaccine strains from Eimeria field isolates. Being able to do that would allow using vaccines in a more targeted way. The objective of this study was to collect Eimeria maxima isolates from broiler flocks that received anticoccidial feed additives and flocks that had been vaccinated against coccidia and then test them with a multilocus sequencing typing (MLST) scheme developed for this study. Fecal samples were obtained from commercial broiler flocks in Alabama and Tennessee. Oocyst counts in samples tended to be lower in flocks receiving anticoccidial feed additives and higher in vaccinated flocks. Selected samples were screened for presence of E. maxima by quantitative PCR, and Eimeria spp. composition was investigated by next-generation amplicon sequencing (NGAS) in 37 E. maxima positive samples. Other detected Eimeria spp. besides E. maxima were Eimeria acervulina in 35 samples, Eimeria praecox in 23 samples, Eimeria mitis or Eimeria mivati in 17 samples, and Eimeria necatrix or Eimeria tenella in 10 samples. Six partial E. maxima genes (dnaJ domain containing protein, 70-kDa heat shock protein, prolyl endopeptidase, regulator of chromosome condensation domain containing protein, serine carboxypeptidase, and vacuolar proton-translocating ATPase subunit) of 46 samples were sequenced. The MLST scheme was able to differentiate two vaccines from each other. Three of 17 samples from vaccinated flocks differed from the vaccine used in the flock, while 16 of 29 samples from unvaccinated flocks differed from the vaccine. However, there was also a large number of low-quality, ambiguous chromatograms and negative PCRs for the selected genes. If and when more advanced, possibly next-generation sequencing-based methods will be developed, the genes should be considered as targets.

Detection of Toxoplasma gondii oocysts in soil and risk mapping in an island environment in the Northeast of Brazil

Toxoplasmosis is an emerging and re-emerging infectious disease that can be transmitted through a contaminated environment. Environmental contamination is an emergency health issue, and determining its occurrence is fundamental to a One Health approach. In this study, we addressed the extent of environmental contamination and viability of Toxoplasma gondii oocysts in soil in different environments on Fernando de Noronha Island, Brazil. In addition, we performed species distribution modelling to predict the environmental suitability for coccidia persistence in the studied area. Soil samples were collected in 14 neighbourhoods of the Island and in the four main squares, creating a total of 95 soil samples (five samples per site). The samples were analyzed by the polymerase chain reaction (PCR) technique for the presence of the 18S ribosomal DNA gene of Apicomplexan protozoa, followed by genetic sequencing. We obtained 4.2% (4/95) positive soil samples with 100% similarity for T. gondii sequences. Two out of four positive sites on PCR showed viability of T. gondii oocysts through the mouse bioassay technique. As a result of the application of the species distribution modelling, environmental adequacy for the coccidia was observed throughout the Island. The results confirm the contamination of the soil in this insular environment by T. gondii oocysts and the environmental suitability by modelling application. These findings are an alert for the possibility of infection in animals and humans by contaminated soil, and for contamination of the maritime environment in addition to water resources for consumption by the local population.

A Coccidia-Specific Phosphate Transporter Is Essential for the Growth of Toxoplasma gondii Parasites

Toxoplasma gondii is an obligate intracellular parasite that acquires all necessary nutrients from the hosts, but the exact nutrient acquisition mechanisms are poorly understood. Here, we identified three putative phosphate transporters in T. gondii. TgPiT and TgPT2 are mainly on the plasma membrane, whereas TgmPT is localized to the mitochondrion. TgPiT and TgmPT are widely present and conserved in apicomplexan parasites that include Plasmodium and Eimeria species. Nonetheless, they are dispensable for the growth and virulence of Toxoplasma. TgPT2, on the other hand, is restricted to coccidia parasites and is essential for Toxoplasma survival. TgPT2 depletion led to reduced motility and invasion, as well as growth arrest of the parasites both in vitro and in vivo. Both TgPiT and TgPT2 have phosphate transport activities and contribute to parasites' inorganic phosphate (Pi) absorption. Interestingly, the Pi importing activity of Toxoplasma parasites could be competitively inhibited by ATP and AMP. Furthermore, direct uptake of 32P-ATP was also observed, indicating the parasites' ability to scavenge host ATP. Nonetheless, ATP/AMP import is not mediated by TgPiT or TgPT2, suggesting additional mechanisms. Together, these results show the complex pathways of phosphate transport in Toxoplasma, and TgPT2 is a potential target for antitoxoplasmic intervention design due to its essential role in parasite growth. IMPORTANCE To grow and survive within host cells, Toxoplasma must scavenge necessary nutrients from hosts to support its parasitism. Transporters located in the plasma membrane of the parasites play critical roles in nutrient acquisition. Toxoplasma encodes a large number of transporters, but so far, only a few have been characterized. In this study, we identified two phosphate transporters, TgPiT and TgPT2, to localize to the plasma membrane of Toxoplasma. Although both TgPiT and TgPT2 possess phosphate transport activities, only the novel transporter TgPT2 was essential for parasite growth, both in vitro and in vivo. In addition, TgPT2 and its orthologs are only present in coccidia parasites. As such, TgPT2 represents a potential target for drug design against toxoplasmosis. In addition, our data indicated that Toxoplasma can take up ATP and AMP from the environment, providing new insights into the energy metabolism of Toxoplasma.

Automated enumeration of Eimeria oocysts in feces for rapid coccidiosis monitoring

Coccidiosis represents a major driver in the economic performance of poultry operations, as coccidia control is expensive, and infections can result in increased feed conversion ratios, uneven growth rates, increased co-morbidities with pathogens such as Salmonella, and mortality within flocks. Shifts in broiler production to antibiotic-free strategies, increased attention on pre-harvest food safety, and growing incidence of anti-coccidial drug resistance has created a need for increased understanding of interventional efficacy and methods of coccidia control. Conventional methods to quantify coccidia oocysts in fecal samples involve manual microscopy processes that are time and labor intensive and subject to operator error, limiting their use as a diagnostic and monitoring tool in animal parasite control. To address the need for a high-throughput, robust, and reliable method to enumerate coccidia oocysts from poultry fecal samples, a novel diagnostic tool was developed. Utilizing the PIPER instrument and MagDrive technology, the diagnostic eliminates the requirement for extensive training and manual counting which currently limits the application of conventional microscopic methods of oocysts per gram (OPG) measurement. Automated microscopy to identify and count oocysts and report OPG simplifies analysis and removes potential sources of operator error. Morphometric analysis on identified oocysts allows for the oocyst counts to be separated into 3 size categories, which were shown to discriminate the 3 most common Eimeria species in commercial broilers, E. acervulina, E. tenella, and E. maxima. For 75% of the samples tested, the counts obtained by the PIPER and hemocytometer methods were within 2-fold of each other. Additionally, the PIPER method showed less variability than the hemocytometer counting method when OPG levels were below 100,000. By automated identification and counting of oocysts from 12 individual fecal samples in less than one hour, this tool could enable routine, noninvasive diagnostic monitoring of coccidia in poultry operations. This approach can generate large, uniform, and accurate data sets that create new opportunities for understanding the epidemiology and economics of coccidia infections and interventional efficacy.

Prevalence and diversity of Eimeria spp. in free-range chickens in northeastern Brazil

In tropical regions, family farming is a form of production and work that is highly present in rural areas. Because the production system for free-range chickens has a low level of technification, it frequently presents massive infection by coccidia. The objective of this study was to determine the prevalence and diversity of Eimeria species in free-range chickens in northeastern Brazil. Fecal analyses were carried out using materials collected from 100 farms, belonging to 10 different municipalities. The sample from each farm was composed of five stool samples collected from different animals. Coproparasitological analyses were performed and, in each positive sample, photomicrographs of 20 oocysts were used for morphological identification of coccidia. The presence of Eimeria spp. was detected in 59% (59/100) of the farms analyzed. Species identification was performed through morphometric analysis of 1,180 sporulated oocysts. The following eight species of Eimeria spp. were found, in decreasing order of prevalence: Eimeria necatrix (25%), Eimeria mitis (18.3%), Eimeria mivati (17.3%), Eimeria tenella (12.4%), Eimeria brunetti (9.9%), Eimeria acervulina (9.1%), Eimeria praecox (4.8%) and Eimeria maxima (3.2%). The prevalence and diversity of Eimeria spp. on farms producing backyard chickens in the semiarid region of Brazil were high, especially the diversity of species. Changing the management, with the adoption of sanitary measures, may be effective in reducing the high prevalence of coccidia on the farms studied.

MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF ENTERIC COCCIDIA ISOLATED FROM BLACK-FOOTED FERRETS (MUSTELA NIGRIPES)

Black-footed ferrets (BFF; Mustela nigripes) are the only ferret species native to North America and have been listed as endangered since 1967. Starting in 1986, a multi-institutional effort has been breeding this species in captivity with successful reintroductions back into the wild. Enteric coccidiosis is recognized as a frequent cause of juvenile morbidity and mortality in captive breeding programs, and can result in substantial population losses. Despite this, little is known about the etiology of coccidiosis in BFF. Coccidia-positive fecal samples (n=12) and formalin-fixed paraffin-embedded intestinal tissues (n=11) were obtained from BFF in the Toronto Zoo (Ontario, Canada) and Louisville Zoo (Kentucky, USA) Species Survival Plan (SSP) populations. Oocyst morphometrics and sequence genotyping at three loci (nuclear 18S rDNA, mitochondrial cytochrome c oxidase subunit I and mitochondrial cytochrome c oxidase subunit III) were conducted to characterize the coccidium or coccidia responsible for disease outbreaks in these ferrets in different age classes and years. Results suggest that a single Eimeria species, E. ictidea, was the cause of enteric coccidiosis in both SSP populations in both juvenile and adult age classes in all years evaluated. Wider research is indicated to determine whether these findings are representative of the broader captive and wild BFF populations.

Efficacy of Ficus sycomorus (Sycamore Fig) Extract on Intestinal Coccidiosis in Experimentally Infected Rabbits

This study was conducted to investigate the effect of the Ficus sycomorus extract on Eimeria intestinalis in experimentally infected rabbits. For this purpose, forty male 30-day-old rabbits (Blanc de Bouscat) were divided into four groups (n = 10 in each group). Rabbits kept in the first group served as negative control (non-treated-non-infected). Rabbits kept in the second, third, and fourth groups were challenged at 10 weeks old with 3 × 10⁴E. intestinalis sporulated oocysts. The third and fourth groups were treated orally with diclazuril 10% (0.05 mg/kg body weight) and F. sycomorus (100 mg/Kg) for three consecutive days, respectively. The efficacy was assessed based on the growth performance parameters, clinical symptoms, oocyst shedding, histopathological findings, and hematological parameters for 16 days post challenge. The study revealed that rabbits treated with F. sycomorus methanolic extract and diclazuril showed mild clinical symptoms with a significant decrease in oocyst shedding compared with the positive control. Moreover, the diclazuril-treated group showed the highest leukocytic count and the lowest monocytes percentage compared with other groups. Furthermore, the lowest lymphocytes percentage was recorded in the control positive group. Histopathologically, moderate coccidia infestation in the intestinal mucosa and moderate hydropic degeneration of hepatocytes were observed in the diclazuril treated group compared with the negative control. However, mild coccidia infestation in the intestinal mucosa and slight coagulative necrosis of hepatocytes was found in the F. sycomorus treated group. In conclusion, F. sycomorus methanolic extract had promising effects on the live performance, oocyst count, and blood variables, while it possesses adverse consequences on the hepatic tissues. Further studies are required to optimize the dose and extraction method to mitigate its side effects.

Coccidial oocyst release: once a day or all day long? Tropical bird hosts shed new light on the adaptive significance of diurnal periodicity in parasite output

Many parasites spend part of their life cycle as infectious forms released from an infected host in the external environment, where they may encounter and infect new hosts. The emergence of infectious life stages often occurs once a day to minimize mortality in adverse environments. In bird hosts, intestinal parasites such as coccidia are generally released with feces in the late afternoon. This dynamic is adaptive since it allows avoiding desiccation and ultraviolet (UV) radiation, thus reducing mortality of oocysts in the environment until transmission to the next host. If this circadian rhythm is the result of natural selection to increase oocyst survival, we may hypothesize that oocysts will appear in feces at different times depending on the environment where hosts live. Particularly, in an environment where UV radiation and desiccation are very low, we may expect oocyst circadian release to disappear since the main selective pressure would be relaxed. We sampled different species of birds in tropical and temperate forests in spring and investigated coccidian oocyst output. A strong circadian variation in the prevalence of hosts shedding coccidian oocyst was detected for species caught in the temperate forest with an increase in prevalence in the late afternoon, whereas prevalence of birds shedding oocysts was constant over the course of the day for most species sampled in the tropical rain forest. These results are consistent with the hypothesis that oocysts’ circadian output is maintained by natural selection to increase oocyst survival. We discuss the adaptive significance of diurnal periodicity in parasite output.

Diversity of Eimeria (Apicomplexa: Eimeriidae) species and risk factors associated in natural infecting calves at the Southern Agreste Microregion in the State of Pernambuco, Brazil

Eimeria species have importance to calves because of the economic losses. The aim of this study was to identify the species of Eimeria that affect calves and the risk factors associated with its natural infection. Fecal samples (387) were collected from dairy farms in the southern Agreste of Pernambuco. The feces were evaluated using the Gordon & Whitlock technique and were cultured in 2.5% potassium dichromate for sporulation of oocysts. Odds ratio (OR) were calculated to assess risk factors. Eimeria spp. were detected in 50.65% (196/387) of the samples. Eleven species were identified, being Eimeria bovis (26.64%; 548/2057), Eimeria zuernii (19.69%; 405/2057) and Eimeria ellipsoidalis (14.49%; 298/2057) those more frequent. Small herds (OR = 1.93), calves aged up to six months (OR = 2.12), absence of manure pit (OR = 7.52), fortnightly cleaning (OR = 4.71), collective calf pens (OR = 3.26), manual milking (OR = 2.16) and absence of veterinary care (OR = 2.28) were considered to be risk factors. The data revealed pathogenic species in more than 50% of the farms. Thus, the importance of adopting sanitary measures to reduce the spread of these protozoa in herds should be done, because of economic losses associated with its infection.

Pharmacokinetics of ponazuril after administration of a single oral dose to green turtles (Chelonia mydas)

The coccidian protozoan, Caryospora cheloniae, has been associated with severe enteritis and encephalitis in immature farm-raised green turtles (Chelonia mydas) in the Cayman Islands, immature green turtles off the coast of Florida, and immature stranded sea turtles in Australia. An effective anti-coccidial drug that is both orally absorbed and well-distributed throughout the body is needed for treatment of turtles diagnosed with coccidiosis in rehabilitation facilities. Ponazuril is a triazine antiprotozoal drug that is approved in the USA for the treatment of another Apicomplexan, Sarcocystis neurona, and has also been successfully used in the therapy of other coccidian parasites. The objective of this study was to perform an oral dose-ranging pilot study (10–100 mg/kg of body weight ponazuril) in green turtles (N = 9), followed by oral administration of ponazuril at 100 mg/kg body weight (N = 8) to assess its disposition. Another goal of this study was to optimize the method of oral drug administration to green turtles. Plasma ponazuril concentrations were quantified using high performance liquid chromatography (HPLC). Standard compartmental models were fit to the data. Ponazuril was absorbed after oral administration at 100 mg/kg BW, with a maximum plasma concentration of 3.3 µg/ml. Dose-dependent pharmacokinetic parameters only weakly correlated with the dose rate, apparently due to considerable pharmacokinetic variability observed between turtles. Administration of ponazuril in gelatin capsules using a balling gun was deemed the least variable and most successful method of drug administration. Further studies are needed to evaluate the safety and efficacy of ponazuril in sea turtles with coccidiosis.

Haemoprotozoa in wild short-beaked echidnas (Tachyglossus aculeatus)

The occurrence and clinical significance of the protozoal parasite reported as Hepatozoon tachyglossi in wild short-beaked echidnas (Tachyglossis aculeatus) have long been uncertain, as has its potential as a prognostic indicator. This retrospective survey of free-ranging short-beaked echidnas admitted to a wildlife hospital used morphological evidence to identify a H. tachyglossi prevalence of 56%, with parasitaemias affecting 0%-36% of monocytes. There was no statistical association between H. tachyglossi intensity and clinical status (P-value = 0.12; 95% confidence interval = 0.1 to 1.3), nor between the presence of H. tachyglossi and age, reason for admission, outcome, season or location. Piroplasms, presumed to be Theileria tachyglossi, were concurrently identified in the erythrocytes of 88% of short-beaked echidnas with no association between age, outcome, season or location, but a statistical association with the location where the animal was found (either on a road, airport runway, exposed urban area, or entangled). Given the current results, intracellular parasitism due to H. tachyglossi may be considered as an incidental finding on haematologic examination of short-beaked echidnas and is likely not an effective prognostic indicator. Further research using molecular tools is required to resolve the uncertain identity of H. tachyglossi which has been based on morphologic characteristics alone.

Coccidia-Microbiota Interactions and Their Effects on the Host

As a common parasitic disease in animals, coccidiosis substantially affects the health of the host, even in the absence of clinical symptoms and intestinal tract colonization. Gut microbiota is an important part of organisms and is closely related to the parasite and host. Parasitic infections often have adverse effects on the host, and their pathogenic effects are related to the parasite species, parasitic site and host-parasite interactions. Coccidia-microbiota-host interactions represent a complex network in which changes in one link may affect the other two factors. Furthermore, coccidia-microbiota interactions are not well understood and require further research. Here, we discuss the mechanisms by which coccidia interact directly or indirectly with the gut microbiota and the effects on the host. Understanding the mechanisms underlying coccidia-microbiota-host interactions is important to identify new probiotic strategies for the prevention and control of coccidiosis.

Anticoccidial Drug Sensitivity of Eimeria Contained in Live Coccidia Vaccines of Broilers, Breeders, and Turkeys

Extensive usage and the limited number of approved poultry anticoccidial drugs has led to some degree of resistance being developed to all drugs. Three independent battery trials were conducted to evaluate the anticoccidial drug sensitivity (AST) of species/strains of Eimeria within three commercial coccidia vaccines. The vaccines used for these studies were Immucox 3^® (broiler vaccine) (IM3), Immucox 5^® (broiler breeder vaccine) (IM5), and Immucox T^® (turkey vaccine) (IMT). Each trial used a randomized block design with six replications. Each cage contained eight male Cobb 500 broilers (IM3 and IM5) or eight male Hy-Line turkeys (IMT). At 12 days of age (D0), birds were group weighed, allocated to treatment cages, and issued weighed treatment feeds. Birds and remaining feed were weighed on D8 (20 days of age) (IM3 and IM5) or D9 (21 days of age (IMT)). Anticoccidial drugs were blended at commercial use levels. The treatments were as follows. IM3: 1) Nonmedicated nonchallenged (NMNC); 2) Nonmedicated challenged (NMC); challenged and medicated with 3) robenidine 33 parts per million (ppm); 4) decoquinate 30 ppm; 5) clopidal 125 ppm; 6) zoalene 125 ppm; 7) diclazuril 1 ppm; 8) amprolium 125 ppm; 9) salinomycin 66 ppm; 10) narasin 39.6 ppm + nicarbazin 39.6 ppm; and 11) narasin 74.25 ppm. IM5 used the same IM3 treatments 1-11 plus 12) nicarbazin. IMT: 1) NMNC; 2) NMC; 3) lasalocid 79.2 ppm; 4) monensin 66 ppm; 5) amprolium 125 ppm; 6) zoalene 125 ppm; and 7) nicarbazin 125 ppm. The challenge for each vaccine was 100 times the commercial recommended dose given orally on D2 (14 days of age). For trials IM3 and IM5, on D8 (6 days postchallenge) all chickens were coccidia lesion scored. IMT oocysts per gram (D7-9) and dropping scores (D8) were determined instead of lesion scores. For IM3 and IM5 vaccines, the results showed that all strains were sensitive to all anticoccidial drugs. For turkey IMT vaccine, the results showed that all strains were highly sensitive to all anticoccidial drugs. This information can serve as a foundation for the use of these coccidia vaccines in the restoration of coccidia sensitivity in the field.

Prevalence of Select Intestinal Parasites in Alabama Backyard Poultry Flocks

Simple Summary

As biosecurity is generally low in backyard chicken flocks, infections with various pathogens are common. This puts other poultry nearby, including commercial flocks, at risk. Some chicken pathogens can also infect humans and cause disease. In this study, backyard poultry flocks were tested for parasites. Eighty-four fecal samples, 82 from chickens and two from turkeys, from 64 backyard flocks throughout the state of Alabama were collected in the summers of 2017 and 2018. The most frequently observed parasites were coccidia, unicellular parasites capable of causing diarrhea. Eggs of various roundworms were observed in 20.3–26.6% of the flocks. These parasites were usually present in low numbers only. Other detected parasites were the flagellates Histomonas meleagridis and Tetratrichomonas gallinarum in 4.7% and 18.8% of flocks. Both can cause severe disease in poultry. Detected parasites that can cause disease in humans were Cryptosporidium spp. in 18.8% of the flocks and Blastocystis spp. in 87.5% of the flocks. The results will help to provide information that can be used to design outreach programs to improve the health and wellbeing of birds in backyard flocks.

Abstract

Keeping chickens as backyard pets has become increasingly popular in the United States in recent years. However, biosecurity is generally low in backyard flocks. As a consequence, they can serve as reservoirs for various pathogens that pose a risk for commercial poultry or human health. Eighty-four fecal samples, 82 from chickens and two from turkeys, from 64 backyard flocks throughout the state of Alabama were collected in the summers of 2017 and 2018. Coccidia oocysts were seen in 64.1% of flocks with oocyst counts in most samples below 10,000 oocysts per gram. Eggs of Ascaridia spp. or Heterakis gallinarum were observed in 20.3% of the flocks, and eggs of Capillaria spp. in 26.6% of the flocks. Egg counts were low, rarely exceeding 1000 eggs per gram. DNA extracted directly from fecal samples was investigated by PCR for other relevant parasites. The results showed that 4.7% of flocks were positive for Histomonas meleagridis, 18.8% of flocks for Tetratrichomonas gallinarum, 18.8% of flocks for Cryptosporidium spp. and 87.5% of flocks for Blastocystis spp. The results will help to provide information that can be used to design outreach programs to improve health and wellbeing of birds in backyard flocks.

Presentation, Clinical Pathology Abnormalities, and Identification of Gastrointestinal Parasites in Camels (Camelus bactrianus and Camelus dromedarius) Presenting to Two North American Veterinary Teaching Hospitals. A Retrospective Study: 1980-2020

Old World Camelids (OWC) represent two species (Camelus bactrianus and Camelus dromedarius) with increasing numbers in North America. Gastrointestinal (GI) parasitism is a major cause of clinical disease in camelids and leads to significant economic impacts. Literature reporting on clinical parasitism of camels is localized to India, Africa, and the Middle East, with limited information available on OWCs in North America. Objectives of this study were to report on clinical presentation and diagnostic findings in Camelus bactrianus and Camelus dromedarius with GI parasitism and provide a comparative analysis between geographic regions. Medical records of OWCs presenting to two veterinary teaching hospitals (of the University of Tennessee and University of Wisconsin) were evaluated. Thirty-one camels including 11 Bactrians and six dromedaries (14 species not recorded) were included for the clinical component of this study, reporting on signalment, presenting complaint, and clinical pathology. Anorexia, weight loss, and diarrhea were the most common presenting complaint. Clinical pathology findings included eosinophilia, hypoproteinemia, and hyponatremia. For the second component of this study, a total of 77 fecal parasite examination results were evaluated for parasite identification and regional variation. Trichuris, Capillaria, Strongyloides, Nematodirus, Dictyocaulus, Moniezia, and protozoan parasites (Eimeria, Cryptosporidium, Giardia) were recorded. Strongyle-type eggs predominated, followed by Trichuris and Eimeria spp. There was a statistically significant variation in prevalence of coccidia between the two regions, with fecal examinations from Tennessee more likely to contain Eimeria (P = 0.0193). Clinicians treating camels in North America should recognize anorexia, weight loss, and diarrhea combined with clinical pathologic changes of hypoproteinemia, eosinophilia and hyponatremia as possible indications of GI parasitism. Clinicians should also consider the potential for regional variation to exist for GI parasites of camels in different areas of North America.

A survey of coccidia and nematodes in pastured poultry in the state of Georgia

The aim of this study was to evaluate and quantify the parasitological challenge in pastured poultry production in the state of Georgia. Over the course of one year, fecal samples from six turkey flocks, ten broiler flocks and 13 layer flocks were collected on a pastured farm in two-week intervals to determine counts of Eimeria oocysts and nematode eggs. Average coccidia counts were 10,198 oocysts per gram of feces (OPG) in broiler flocks, 1,470 OPG in layer flocks and 695 OPG in turkey flocks. The means in broiler and turkey flocks were higher at their first week on pasture. Counts in broilers and layers were significantly higher in spring than in winter and summer. Coccidia counts in broilers were lower than published numbers in conventionally reared poultry, indicating the rotation system of the pastures might effectively reduce the infection pressure. Next-generation sequencing of PCR products showed the presence of most described Eimeria spp. in broilers, layers, and turkeys. In addition, Operational Taxonomic Units (OTUs) x, y and z were found. The frequency of species was similar for broilers and layers, with the exception that Eimeria praecox and OTU z were more common in layers. In layer flocks, the average count of roundworm eggs per gram of feces (EPG) was 509 EPG with 80% of the samples being positive. The mean counts had no clear pattern related to age. There was an increase of EPG with the increase of temperatures during spring and summer with the peak at mid-fall. Worm eggs from laying hens were identified as A. galli. The seasonal differences suggest that higher temperatures might result in an increase of egg survival and sporulation in the environment.

Pathogenesis of Isospora amphiboluri in Bearded Dragons (Pogona vitticeps)

Isospora amphiboluri is a common coccidian found in captive bearded dragons (Pogona vitticeps). To minimize the impact of this parasite, it is important to characterize its pathogenesis so that we can develop appropriate methods for diagnosis and treatment. Forty-five juvenile bearded dragons were used for this two-part study. In the first part, ten bearded dragons were infected with 20,000 oocysts per os, while a control group of five animals received only water. Feces were collected over 45 days and screened for oocysts. In the second part, thirty bearded dragons were used to characterize the pathogenesis of I. amphiboluri. Twenty-five bearded dragons were infected as described previously, while five animals served as controls. Five infected bearded dragons and one control were humanely euthanized on days 4, 8, 12, 16, and 20 post-infection for complete necropsies. The pre-patent period for I. amphiboluri was found to be 18.6 ± 1.9 days (range 15-22 days). Histopathology confirmed that I. amphiboluri follows a homoxenous life cycle. Infections begin in the duodenum and progress to the colon over time. The findings of this study can be used to develop better quarantine and treatment protocols for captive bearded dragons.

The effects of tributyrin supplementation on weight gain and intestinal gene expression in broiler chickens during Eimeria maxima-induced coccidiosis

Butyrate is a feed additive that has been shown to have antibacterial properties and improve gut health in broilers. Here, we examined the performance and gene expression changes in the ileum of tributyrin–supplemented broilers infected with coccidia. Ninety-six, Ross 708 broilers were fed either a control corn–soybean–based diet (−BE) or a diet supplemented with 0.25% (w/w) tributyrin (+BE). Birds were further divided into groups that were inoculated with Eimeria maxima oocysts (EM) or sham-inoculated (C) on day 21 posthatch. At 7 d postinfection (7 d PI), the peak of pathology in E. maxima infection, tributyrin-supplemented birds had significantly improved feed conversion ratios (FCR, P < 0.05) and body weight gain (BWG, P < 0.05) compared with -BE-infected birds, despite both groups having similar feed intake (FI, P > 0.05). However, at 10 d post-infection (10 d PI) no significant effects of feed type or infection were observed. Gene expression in the ileum was examined for insights into possible effects of infection and tributyrin supplementation on genes encoding proteins related to immunity, digestion, and gut barrier integrity. Among immune-related genes examined, IL-1B and LEAP2 were only significantly affected at 7 d PI. Transcription of genes related to digestion (APN, MCT1, FABP2, and MUC2) were primarily influenced by infection at 7 d PI and tributyrin supplementation (FABP2 and MUC2) at 10 d PI. With exception of ZO1, tight junction genes were affected by either infection or feed type at 7 d PI. At 10 d PI, only CLDN1 was not affected by either infection or feed type. Overall tributyrin shows promise as a supplement to improve performance during coccidiosis in broiler chickens; however, its effect on gene expression and mode of action requires further research.

Risk Factors and Severity of Gastrointestinal Parasites in Selected Small Ruminants from Malaysia

The productivity of smallholder sheep and goat flocks is constrained by high morbidity and mortality of young stock due to helminthosis and coccidiosis. We hypothesized that gastrointestinal parasites are prevalent and may cause severe infections amongst small ruminants in Malaysia. A cross-sectional survey was conducted between March and December 2019 to investigate the prevalence, risk factors, and levels of infection with gastrointestinal strongyle and coccidia in selected smallholder goat flocks in Negeri Sembilan, Malaysia. A total of 257 blood and fecal samples and management data were collected from four farms in Negeri Sembilan. Gastrointestinal parasites were detected by routine sodium chloride floatation, and the McMaster technique was used to quantify the fecal eggs/oocysts per gram outputs (EPG/OPG). The severity of infection was classified as mild (50–799), moderate (800–1200), or severe (>1200). The packed cell volume (PCV) was determined by microhematocrit centrifugation and classified as anemic or non-anemic. Coprological examination revealed an overall prevalence of 78.6% (CI = 72.74–83.44) and 100% flock level prevalence of strongyle and coccidia infection among goats from Negeri Sembilan with a higher infection in flock A-Lenggeng (95.6%) than B-Senawang (87.3%), D-Mendom (80.6%), or C-Seremban (60.0%). The co-infections of strongyle + Eimeria (50.6; CI = 44.50 to 56.64) were more common than single infections of either strongyle (16.7%; CI = 12.66 to 21.78) or Eimeria (4.3%; CI = 2.41 to 7.50). Quantitative analysis has revealed different (p < 0.05) patterns of EPG/OPG in various categories of goats. In total, there were 49.8% mild, 8.6% moderate, and 13.6% severe infections of strongyle and 40.1% mild, 6.6% moderate, and 19.8% severe infections of coccidia among goats. The mean PCV of goats with severe strongyle infection (24.60 ± 0.85) was significantly (p < 0.05) lower than the moderate (26.90 ± 1.15), or mild (28.23 ± 0.50) infections and the uninfected (30.4 ± 0.71). There were increased odds of infection with strongyle and coccidia among female (OR = 3.2) and adult (OR = 11.0) goats from smallholder flocks in Negeri Sembilan. In conclusion, gastrointestinal strongyles and coccidia occur at high frequency among smallholder goats, and there is a higher risk of infection amongst the adult and female stock.

Comparisons of the Sexual Cycles for the Coccidian Parasites Eimeria and Toxoplasma

Toxoplasma gondii and Eimeria spp. are widely prevalent Coccidian parasites that undergo sexual reproduction during their life cycle. T. gondii can infect any warm-blooded animal in its asexual cycle; however, its sexual cycle is restricted to felines. Eimeria spp. are usually restricted to one host species, and their whole life cycle is completed within this same host. The literature reviewed in this article comprises the recent findings regarding the unique biology of the sexual development of T. gondii and Eimeria spp. The molecular basis of sex in these pathogens has been significantly unraveled by new findings in parasite differentiation along with transcriptional analysis of T. gondii and Eimeria spp. pre-sexual and sexual stages. Focusing on the metabolic networks, analysis of these transcriptome datasets shows enrichment for several different metabolic pathways. Transcripts for glycolysis enzymes are consistently more abundant in T. gondii cat infection stages than the asexual tachyzoite stage and Eimeria spp. merozoite and gamete stages compared to sporozoites. Recent breakthroughs in host-pathogen interaction and host restriction have significantly expanded the understating of the unique biology of these pathogens. This review aims to critically explore advances in the sexual cycle of Coccidia parasites with the ultimate goal of comparing and analyzing the sexual cycle of Eimeria spp. and T. gondii.

Sodium butyrate and monensin supplementation to postweaning heifer diets: Effects on growth performance, nutrient digestibility, and health

The objective of this study was to evaluate growth and performance of postweaning heifers supplemented with monensin (MON), sodium butyrate (SB), or the combination of MON and SB (MSB) compared with heifers not receiving these feed additives. Forty Holstein heifers [mean age 84.2 ± 1.2 d; body weight (BW) 99.8 ± 10.8 kg (mean ± SD)] were housed in a freestall barn, blocked by birth date, and randomly assigned to 1 of 4 treatments in a randomized complete block design. Treatments were (1) 100 g of soybean meal carrier (control; CON); (2) 0.75 g of SB/kg of BW + carrier (SB); (3) 1 mg of MON/kg of BW + carrier (MON); (4) 1 mg of MON/kg of BW + 0.75 g of SB/kg of BW (MSB). Data were analyzed using single degree of freedom contrasts evaluating CON versus additives (ADD), SB versus MON, and SB and MON versus MSB. Treatments were hand-mixed daily. Feed and orts were measured daily and frozen at -20°C. Orts samples were subsampled for dry matter (DM) determination, and total mixed ration samples were taken weekly and composited monthly for DM and nutrient analysis. Initial BW, heart and paunch girths, body length, blood samples, and fecal coccidia counts were measured before the start and weekly during the 12-wk trial. Blood samples were analyzed for glucose, plasma urea nitrogen (PUN), and ketone concentrations. Apparent total-tract nutrient digestibility was determined from d 21 to 27 and from d 63 to 69 using acid detergent insoluble ash as a marker. Daily dry matter intake (DMI) and metabolizable energy intake were increased in ADD compared with CON, and average BW, final BW, and heart girth tended to increase. Whereas MSB tended to be greater than SB and MON for heart girth, feed efficiency was greater with MON compared with SB. Compared with CON, ADD decreased coccidia counts. No effect of treatment on PUN was detected. Monensin and SB tended to have greater plasma glucose than MSB did. Average blood ketone concentrations were greater with ADD versus CON, in SB versus MON, and in MSB versus SB and MON. During the wk-3 digestibility phase, DMI tended to be greater in heifers fed SB versus MON, as well as in heifers fed MSB versus SB and MON. Digestibility of nutrients were similar, except that starch digestibility was increased in heifers fed MSB versus SB and MON. During the wk-9 digestibility phase, DMI and digestibility of nutrients were similar, except NDF, which tended to be greater in CON than in ADD. Overall, ADD resulted in positive growth and reduced coccidia compared with CON.

In vitro Anticoccidial Study of Oregano and Garlic Essential Oils and Effects on Growth Performance, Fecal Oocyst Output, and Intestinal Microbiota in vivo

This study investigated the in vitro effects of Greek oregano and garlic essential oils on inhibition of Eimeria parasites and their in vivo effects on production performance, intestinal bacteria counts, and oocyst output. An inhibition assay was performed in vitro using Eimeria tenella Wisconsin strain sporozoites and Madin-Darby bovine kidney (MDBK) cells. Intracellular sporozoite invasion was quantified by detection of E. tenella DNA using qPCR from cell monolayers harvested at 2 and 24 h post-infection. Parasite invasion was inhibited by the oregano essential oil at the concentration of 100 μg/ml by 83 or 93% after 2 or 24 h, respectively. Garlic essential oil reached a maximum inhibition of 70% after 24 h with the 50 μg/ml concentration. Normal morphology was observed in MDBK cells exposed to concentrations of 100 μl/ml of garlic or oregano for over 24 h. In the in vivo trial, 180 male broiler chicks (45.3 ± 0.7 g) were allocated into two treatments (6 pens of 15 chicks per treatment). Control treatment was fed commercial diets without antibiotics or anticoccidials. The ORE-GAR treatment was fed the same control diets, further supplemented with a premix (1 g/kg feed) containing the oregano (50 g/kg premix) and garlic (5 g/kg premix) essential oils. At day 37, all birds were slaughtered under commercial conditions, and intestinal samples were collected. ORE-GAR treatment had improved final body weight (1833.9 vs. 1.685.9 g; p < 0.01), improved feed conversion ratio (1.489 vs. 1.569; p < 0.01), and reduced fecal oocyst excretion (day 28: 3.672 vs. 3.989 log oocysts/g, p < 0.01; day 37: 3.475 vs. 4.007 log oocysts/g, p < 0.001). In the caecal digesta, ORE-GAR treatment had lower total anaerobe counts (8.216 vs. 8.824 CFU/g; p < 0.01), whereas in the jejunum digesta the ORE-GAR treatment had higher counts of E. coli (5.030 vs. 3.530 CFU/g; p = 0.01) and Enterobacteriaceae (5.341 vs. 3.829 CFU/g; p < 0.01), and lower counts of Clostridium perfringens (2.555 vs. 2.882 CFU/g; p < 0.01). In conclusion, the combined supplementation of oregano and garlic essential oils had a potent anticoccidial effect in vitro and a growth-promoting effect in broilers reared in the absence of anticoccidial drugs.

Eimeria sciurorum (Apicomplexa, Coccidia) From the Calabrian Black Squirrel (Sciurus meridionalis): An Example of Lower Host Specificity of Eimerians

Host specificity plays one of the key roles in parasitism. It affects the evolution and diversification of both host and parasite, as well as it influences their geographical distribution, and epidemiological significance. For most of parasites, however, host specificity is unknown or misrepresented because it is difficult to be determined accurately. Here we provide the information about the lower host specificity of Eimeria sciurorum infecting squirrels, and its new host record for the Calabrian black squirrel Sciurus meridionalis, a southern Italian endemic species.

Evaluation of Next-Generation Amplicon Sequencing to Identify Eimeria spp. of Chickens

Identifying Eimeria spp. circulating in a poultry flock assists in designing vaccine preventive programs, as different species do not cross-protect. Because species differ in anticoccidial drug susceptibility, species identification can also be used to optimize anticoccidial medication. In the present study, we designed pan-Eimeria-specific primers for the 18S rDNA and the cytochrome oxidase I (COI) genes, and tested whether next-generation sequencing of their amplicons allowed reliable identification of Eimeria spp. in samples of isolated oocysts. For each gene, two sets of primers to be used in a nested PCR (nPCR) system were designed. In silico evaluation of the primers using published sequences showed that nucleotide sequence identities of the nested amplicons were less than 97% between most species, while only identities of 18S rDNA genes of Eimeria necatrix and Eimeria tenella and between the COI genes of Eimeria mitis and Eimeria mivati were higher than 97%. Three vaccines and five Eimeria samples from chickens in backyard flocks were investigated by nPCRs and by direct PCRs (dPCR) using the nested (inner) primers with genomic DNA as the template. Seventeen further Eimeria samples from chickens in backyard flocks and three Eimeria samples from commercial broiler flocks were investigated only by nPCR. Sequencing nPCR products tended to detect more species than sequencing dPCR products and sequencing 18S rDNA products tended to detect more species than sequencing COI products. Regarding the detected species, there was a clear difference between the commercial broiler flocks and the backyard flocks. Eimeria acervulina, Eimeria maxima, and E. tenella/E. necatrix were the only species detected in broiler flocks, while the population in the backyard flocks was more varied, with Eimeria brunetti and E. mitis/E. mivati and the previously described operational taxonomic unit Y being more prevalent. Several sequences having less than 97% identity with one of the sequences used for clustering were detected in samples from backyard flocks. In conclusion, next-generation amplicon sequencing can be a useful tool to determine which Eimeria spp. are circulating in chicken flocks.

Essential function of the alveolin network in the subpellicular microtubules and conoid assembly in Toxoplasma gondii

The coccidian subgroup of Apicomplexa possesses an apical complex harboring a conoid, made of unique tubulin polymer fibers. This enigmatic organelle extrudes in extracellular invasive parasites and is associated to the apical polar ring (APR). The APR serves as microtubule-organizing center for the 22 subpellicular microtubules (SPMTs) that are linked to a patchwork of flattened vesicles, via an intricate network composed of alveolins. Here, we capitalize on ultrastructure expansion microscopy (U-ExM) to localize the Toxoplasma gondii Apical Cap protein 9 (AC9) and its partner AC10, identified by BioID, to the alveolin network and intercalated between the SPMTs. Parasites conditionally depleted in AC9 or AC10 replicate normally but are defective in microneme secretion and fail to invade and egress from infected cells. Electron microscopy revealed that the mature parasite mutants are conoidless, while U-ExM highlighted the disorganization of the SPMTs which likely results in the catastrophic loss of APR and conoid.

PREVALENCE AND PARASITE COMPOSITION OF GASTROINTESTINAL PARASITES IN THE ENDANGERED TIBETAN ANTELOPE (PANTHOLOPS HODGSONII) FROM THE CALVING GROUND OF HOH XIL NATURE WORLD HERITAGE SITE, QINGHAI, CHINA

Our objective was to provide baseline information on the gastrointestinal parasites of the female Tibetan antelope (Pantholops hodgsonii) on its calving ground at the Zhuonai Lake region, in the Hoh Xil Nature World Heritage site, Qinghai, China. On 3 July 2018, 238 freshly deposited fecal samples were collected from the calving grounds and analyzed by flotation technique to recover eggs, oocysts, and nematode larvae. All fecal samples demonstrated the presence of gastrointestinal parasites: 93% (221/238) had nematodes, 36% (86/238) had cestodes, and 99% (235/238) had coccidian oocysts. For each Tibetan antelope, mean (SD) parasite species richness was 3.4 (1.3). Coinfections with five parasite genera were found in 19% (45/238) of fecal samples. These results showed that prevalence of Trichostrongylus, Marshallagia, and Eimeria infections in these Tibetan antelopes were sufficiently high to suggest long-term monitoring be implemented because the climate there is becoming warmer and moisture is increasing, both presumably due to the influence of global warming which, in turn, may be contributing to increased infection risks with these parasites.

Eimeria tamimi sp. n. (Apicomplexa: Eimeriidae) from the rock hyrax (Procavia capensis jayakari) in central Saudi Arabia

Faecal samples from the rock hyrax (Procavia capensis jayakari Thomas) were collected from the Ibex Reserve in central Saudi Arabia. Eimerian oocysts, which are believed to represent a new species described here as Eimeria tamimi sp. n., were detected in 40 out of 93 samples. Oocysts were fully sporulated in 24-48 hours at 25 ± 2 °C. Sporulated oocysts of E. tamimi sp. n. were ovoid, measuring 35-42 × 19-25 μm (39 × 23 μm), a length/width ratio 1.5-2 (1.7). Oocyst wall was bilayered and measured 1.5 μm in thickness. Micropyle, oocyst residuum and polar granules were not present. Sporocysts are elongate, measuring 12-18 × 9-12 μm (15 × 10 μm), with a length/width ratio 1.1-1.8 (1.5) prominent Stieda bodies and sporocyst residuum. Experimental infection of two clinically healthy rock hyraxes with sporulated oocysts of E. tamimi sp. n. resulted in shedding unsporulated oocysts 5-10 days post infection. Partial sequences of 18S ribosomal RNA (18S rDNA) and cytochrome C oxidase subunit 1 (COI) regions were amplified using the polymerase chain reaction (PCR) and sequenced. Phylogenetic analysis based on 18S rDNA using maximum likelihood (ML) and Bayesian inference (BI) methods revealed that E. tamimi sp. n. grouped with Eimeria quokka Barker, O'Callaghan et Beveridge, 1988, E. mundayi Barker, O´Callaghan et Beveridge, 1988, E. potoroi Barker, O'Callaghan et Beveridge, 1988 and E. gaimardi Barker, O'Callaghan et Beveridge, 1988 marsupials. Eimerian species have been regarded as a paraphyletic group and the present investigation confirmed the conflict between phenotypic traits, used widely in the classification of this group of parasites.

Oral antibody to interleukin-10 receptor 2, but not interleukin-10 receptor 1, as an effective Eimeria species immunotherapy in broiler chickens

Coccidiosis is a major gastrointestinal disease caused by several Eimeria species in floor raised chickens. Feeding an antibody to interleukin 10 (aIL-10) ameliorates the negative symptoms of coccidiosis in broilers, i.e., lack of weight gain, decreased feed conversion, and mortality. IL-10 signals by forming a ligand-receptor complex with IL-10 Receptor 1 (IL-10 R1) and IL-10 Receptor 2 (IL-10 R2). In this study, we hypothesize oral antibodies to the IL-10 receptors will neutralize the IL-10 signaling pathway equal to or better than aIL-10 to act as an oral anti-coccidiosis immunotherapy. A total of 5 sequential feed trials, set up as a 4 (diet antibody) × 2 (Eimeria challenge) factorial design, tested oral egg yolk antibodies to a total of 6 IL-10 R1 epitopes and 3 IL-10 R2 epitopes compared to a control antibody diet. A total of 10 pens of 5 chicks/pen/diet antibody/Eimeria challenge were housed for 21 d. On day 3 of age, chicks were either infected or not infected with a 10× dose of an Eimeria vaccine containing Eimeria acervulina, Eimeria tenella, and Eimeria maxima. Pen feed consumption and mean body weights were assessed weekly (d1, d7, d14, and d21); fecal oocyst shedding was assessed on day 10. Data were analyzed using a 2-way ANOVA. No significant interaction on chick weight was observed in chicks fed IL-10 R1 antibodies compared to chicks fed the control antibody was observed. In studies evaluating aIL-10 R2 oral antibodies, infected chicks fed aIL-10 R2: epitope 1 overcame the negative effects of Eimeria infection and had similar 21-d body weight to uninfected chicks (P4 = 0.07). We hypothesized that feeding oral antibodies to the IL-10 receptors would result in equivalent anti-coccidial benefits to aIL-10. However, none of the 6 antibodies to IL-10 R1 epitopes yielded any benefits during Eimeria infection compared to controls. A total of 2 oral antibodies to IL-10 R2 showed promising results equivalent to the aIL-10 immunotherapeutic. Immunofluorescence staining shows that the IL-10R2 significantly increases in abundance in response to Eimeria infection, whereas IL-10R1 does not.

Life cycle stages, specific organelles and invasion mechanisms of Eimeria species

Apicomplexans, including species of Eimeria, pose a real threat to the health and wellbeing of animals and humans. Eimeria parasites do not infect humans but cause an important economic impact on livestock, in particular on the poultry industry. Despite its high prevalence and financial costs, little is known about the cell biology of these 'cosmopolitan' parasites found all over the world. In this review, we discuss different aspects of the life cycle and stages of Eimeria species, focusing on cellular structures and organelles typical of the coccidian family as well as genus-specific features, complementing some 'unknowns' with what is described in the closely related coccidian Toxoplasma gondii.

Histologic Effects of Concurrent Heat Stress and Coccidial Infection on the Lymphoid Tissues of Broiler Chickens

We characterized the histologic effects of two stressors (heat and coccidial infection) alone or in combination on bursa of Fabricius, thymus, and spleen in broiler chickens. Four hundred and eighty Cobb500 male chicks at 14 days of age were randomly assigned to two treatments in a 2×2 factorial design, with 15 replicates per treatment and eight birds per replicate. The treatment factors were temperature (25 and 35 C) and a mixed culture of 2.5 × 10⁵ sporulated Eimeria acervulina and Eimeria maxima oocysts (infection or no infection). Histologic lesion severity was scored in these tissues at different ages. At 21 and 28 days of age, bursal and thymic tissues from birds raised at 35 C exhibited significant increases in lymphoid depletion severity compared with those raised at 25 C. No significant differences were detected in the lymphoid depletion severity of birds infected with Eimeria when compared with uninfected birds. These results indicate that continuous exposure to heat stress-inducing temperatures results in lymphoid depletion of the bursa and thymus in broiler chickens, a potential histologic marker for the immunologic changes known to arise as a result of heat stress. Bursal and thymic atrophy are thought to contribute to immunologic changes that underlie the negative effects of heat stress on poultry production characteristics.

Pathology caused by three species of Eimeria that infect the turkey with a description of a scoring system for intestinal lesions

Three-week-old turkey poults were infected with pure lines of three species of Eimeria (E. adenoeides, E. gallopavonis, and E. meleagrimitis) recently isolated from commercial turkey farms. The lines had been propagated from a single oocyst and identified by species-specific PCR amplification of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Five to six days after infection their intestines were removed and examined for the presence of intestinal lesions. A description and review of the pathology caused by these parasites is provided, and a scoring system developed by which the severity of the lesions can be evaluated. The system is similar to that described by Johnson, J. and Reid, W. M. [1970. Anticoccidial drugs: lesion scoring techniques in battery and floor-pen experiments with chickens. Experimental Parasitology, 28, 30-36] for chickens in which a score of zero to four is assigned to lesions of increasing severity. The intestinal lesions observed here, and their assigned scores, are supported by representative illustrations. It is hoped that they may prove a useful tool for evaluating the pathology caused by E. adenoeides, E. gallopavonis, and E. meleagrimitis in the turkey.RESEARCH HIGHLIGHTSA scoring system has been developed for intestinal lesions caused by three species of Eimeria that infect the turkey.The lesions attributable to these species are illustrated.

Interactions Between Parasites and the Bacterial Microbiota of Chickens

Except for the important role coccidia have as predisposing factors of necrotic enteritis, the role parasites play in the dynamics of a healthy microbiota of chickens is not well explored. This review describes the interactions of relevant intestinal parasites of chickens with bacteria. Infection with Eimeria spp. favor the growth of Clostridium perfringens and suppress the growth of many other bacteria by increasing viscosity and passage time of the ingesta, and by causing lesions to the intestinal mucosa that improve the availability of nutrients for C. perfringens. Conversely, there are indications that bacteria influence the course of disease after infections with Eimeria spp. Not much is known about intestinal cryptosporidiosis in chickens, but results in mice show that the intestinal microbiota induces some resistance against infection with Cryptosporidium parvum and that the innate immune response triggered by infections with cryptosporidia might have an effect on other intestinal microbes. Histomonas meleagridis depend on bacteria in vitro, and in vivo it will cause lesions in chickens only in the presence of bacteria. Blastocystis spp. are very common in chickens, but there is no information about interactions with bacteria. In humans, there is evidence of the correlation of the detection of Blastocystis and changes in the intestinal microbiota. There are indications of interactions between Ascaridia galli and various bacteria in chickens and Ascaridia spp. of mammals are known to produce various types of antimicrobial molecules. However, often the underlying mechanisms of these interactions between parasites and bacteria remain unknown and only correlations but not causation can be established.

Effects of Ground Floor Type on Selected Health-Parameters and Weight of Rabbits Reared in Group Pens

Simple Summary

Cage housing of growing rabbits is associated with welfare concerns. An alternative system that has already been introduced involves pens with non-wire floors. An important aspect of group pens, for which the best solution has not yet been clearly demonstrated, is the choice of floor material. We investigated effects of two ground floor types—slatted plastic floor versus concrete floor with straw litter—on health-related parameters and weight of rabbits reared in large group pens on a commercial rabbit farm, i.e., with preventive coccidiostatic, and if required, additional therapeutic medical treatment. Pens were identical in dimensions, equipment (including platforms), and initial group size (60 animals/pen). Four pens were studied per ground floor type in three consecutive rearing periods, i.e., 12 pens/ground floor type. A higher percentage of rabbits per pen had clean fur if reared on straw. No significant differences were found in parasitic burden, mortality, pathological alterations, or causes of loss. Thus, often-expressed concerns that parasitic load and mortality would be higher in groups kept on straw were not confirmed when rabbits were housed under otherwise equal conditions. Average slaughter weight was higher in rabbits reared on a slatted plastic floor, confirming previous findings of a negative impact of straw litter on weight gain.

Abstract

Cage housing of growing rabbits is associated with welfare concerns. An alternative system that has already been introduced involves pens with non-wire floors. An important aspect of group pens, for which the best solution has not yet been clearly demonstrated, is the choice of floor material. The study investigated effects of two ground floor types—slatted plastic floor versus concrete floor with straw litter—on health-related parameters and weight of rabbits reared in large group pens on a commercial rabbit farm, i.e., with preventive coccidiostatic, and if required, additional therapeutic medical treatment. Pens were identical in dimensions, equipment (including platforms), and initial group size (60 animals/pen). Four pens were studied per ground floor type in three consecutive rearing periods (in total, 12 pens per floor type). A higher percentage of rabbits per pen had clean fur if reared on straw (p < 0.05). No significant differences were found in the load of coccidial oocysts in collective faecal samples, mortality, pathological alterations, or causes of loss (p > 0.05). Thus, often-expressed concerns that parasitic load and mortality would be higher in groups kept on straw were not confirmed when rabbits were housed under otherwise equal conditions. Average slaughter weight was higher in rabbits reared on a slatted plastic floor (p < 0.05), confirming previous findings of a negative impact of straw litter on weight gain.

Supplementation of sodium butyrate to postweaned heifer diets: Effects on growth performance, nutrient digestibility, and health

The objective of this study was to determine the effect of varying levels of sodium butyrate (SB) supplementation in feed on the growth, digestibility, and health of postweaned heifers. Forty Holstein dairy heifers with a mean age of 84 d and average body weight (BW) of 100.9 ± 11.2 kg were housed in a naturally ventilated freestall barn. Heifers were blocked by birth date and randomly assigned to 1 of 4 treatments in a completely randomized block design: (1) 100 g of soybean meal carrier (control), (2) 0.25 g of SB/kg of BW plus carrier, (3) 0.50 g of SB/kg of BW plus carrier, and (4) 0.75 g of SB/kg of BW plus carrier. Carrier with or without SB was top-dressed and hand-mixed into a total mixed ration once daily. Heifers were fed to provide 10% orts. Initial BW, hip and withers heights, heart girth, and body length were measured before the start of the study and every week thereafter until the 14-wk trial was over. Blood samples were obtained and plasma urea nitrogen, plasma glucose, and whole-blood β-hydroxybutyrate concentrations were determined before the start of treatment and weekly thereafter until the conclusion of the study. Fecal samples were taken before treatment and every other week from each heifer for coccidia counts. Apparent total-tract nutrient digestibility was determined using acid detergent insoluble ash as an internal marker. Each heifer underwent this phase from d 47 until d 54 of the study. Sodium butyrate had a positive effect on average BW and overall BW gain. Feed efficiency tended to improve as SB supplementation increased. Coccidia counts were lowest in the treatment with 0.25 g of SB/kg of BW plus carrier. Sodium butyrate had no effects on skeletal growth or plasma urea nitrogen concentration. Blood glucose concentration decreased linearly and β-hydroxybutyrate increased linearly with increasing levels of SB supplementation. Sodium butyrate supplementation did not affect apparent total-tract nutrient digestibility. Sodium butyrate supplementation offers positive results in the growth performance and feed efficiency of postweaned heifers.

Molecular detection of Cyclospora cayetanensis in human stool specimens using UNEX-based DNA extraction and real-time PCR

Cyclospora cayetanensis is a coccidian parasite associated with diarrheal illness. In the USA, foodborne outbreaks of cyclosporiasis have been documented almost every year since the mid-1990s. The typical approach used to identify this parasite in human stools is an examination of acid-fast-stained smears under bright-field microscopy. UV fluorescence microscopy of wet mounts is more sensitive and specific than acid-fast staining but requires a fluorescence microscope with a special filter not commonly available in diagnostic laboratories. In this study, we evaluated a new DNA extraction method based on the Universal Nucleic Acid Extraction (UNEX) buffer and compared the performances of four published real-time polymerase chain reaction (PCR) assays for the specific detection of C. cayetanensis in stool. The UNEX-based method had an improved capability to recover DNA from oocysts compared with the FastDNA stool extraction method. The best-performing real-time PCR assay was a C. cayetanensis-specific TaqMan PCR that targets the 18S ribosomal RNA gene. This new testing algorithm should be useful for detection of C. cayetanensis in human stool samples.

Recolonizing gray wolves increase parasite infection risk in their prey

The recent recolonization of Central Europe by the European gray wolf (Canis lupus) provides an opportunity to study the dynamics of parasite transmission for cases when a definitive host returns after a phase of local extinction. We investigated whether a newly established wolf population increased the prevalence of those parasites in ungulate intermediate hosts representing wolf prey, whether some parasite species are particularly well adapted to wolves, and the potential basis for such adaptations. We recorded Sarcocystis species richness in wolves and Sarcocystis prevalence in ungulates harvested in study sites with and without permanent wolf presence in Germany using microscopy and DNA metabarcoding. Sarcocystis prevalence in red deer (Cervus elaphus) was significantly higher in wolf areas (79.7%) than in control areas (26.3%) but not in roe deer (Capreolus capreolus) (97.2% vs. 90.4%) or wild boar (Sus scrofa) (82.8% vs. 64.9%). Of 11 Sarcocystis species, Sarcocystis taeniata and Sarcocystis grueneri occurred more often in wolves than expected from the Sarcocystis infection patterns of ungulate prey. Both Sarcocystis species showed a higher increase in prevalence in ungulates in wolf areas than other Sarcocystis species, suggesting that they are particularly well adapted to wolves, and are examples of "wolf specialists". Sarcocystis species richness in wolves was significantly higher in pups than in adults. "Wolf specialists" persisted during wolf maturation. The results of this study demonstrate that (1) predator-prey interactions influence parasite prevalence, if both predator and prey are part of the parasite life cycle, (2) mesopredators do not necessarily replace the apex predator in parasite transmission dynamics for particular parasites of which the apex predator is the definitive host, even if meso- and apex predators were from the same taxonomic family (here: Canidae, e.g., red foxes Vulpes vulpes), and (3) age-dependent immune maturation contributes to the control of protozoan infection in wolves.