A morphological and molecular comparison of Eimeria bovis-like oocysts (Apicomplexa: Eimeriidae) from European bison, Bison bonasus L., and cattle, Bos taurus L., and the development of two multiplex PCR assays for their identification

Development of a PCR assay for detection and identification of Eimeria spp. in cattle

Eimeria spp. are important coccidian parasites causing diarrhea and significant mortality in cattle worldwide. To date, at least 13 Eimeria species with varying pathogenicity have been identified in cattle. Efficient detection and identification of Eimeria spp. is therefore essential for the prevention and control of bovine coccidiosis. However, the commonly used microscopic examination for Eimeria spp. is time-consuming and requires considerable expertise. In this study, we aligned the nucleotide sequences of the small subunit (SSU) rRNA gene of common Eimeria species and developed a nested PCR assay targeting the polymorphic SSU rRNA region of Eimeria spp. from cattle. Initially, the SSU rRNA gene PCR assay was compared with microscopic examination for sensitivity and detection range of Eimeria species using fecal samples from dairy cattle. Of the 193 fecal samples, 131 (67.9 %) and 78 (40.4 %) were positive for Eimeria by PCR and microscopy, respectively. Sequence analysis of the PCR products identified six Eimeria species, including E. cylindrica (n = 76), E. bovis (n = 54), E. auburnensis (n = 30), E. zuernii (n = 25), E. wyomingensis (n = 10), E. canadensis (n = 1), and co-infections of 2-4 species (n = 55). In contrast, only the first four species and co-infections of 2-3 species were identified by microscopy. The PCR assay was able to detect as few as 50 Eimeria oocysts per gram of feces. Thus, the developed SSU rRNA gene PCR assay has a high sensitivity and allowed easy identification of at least six common Eimeria species and their co-infections in cattle. It should be useful in molecular epidemiological studies of bovine coccidiosis.

Eimeria zuernii (Eimeriidae: Coccidia): mitochondrial genome and genetic diversity in the Chinese yak

BACKGROUND

Coccidiosis caused by Eimeria zuernii (Eimeriidae: Coccidia) represents a significant economic threat to the bovine industry. Understanding the evolutionary and genetic biology of E. zuernii can assist in new interaction developments for the prevention and control of this protozoosis.

METHODS

We defined the evolutionary and genetic characteristics of E. zuernii by sequencing the complete mitogenome and analyzing the genetic diversity and population structure of 51 isolates collected from eight yak breeding parks in China.

RESULTS

The 6176-bp mitogenome of E. zuernii was linear and encoded typical mitochondrial contents of apicomplexan parasites, including three protein-coding genes [PCGs; cytochrome c oxidase subunits I and III (cox1 and cox3), and cytochrome b (cytb)], seven fragmented small subunit (SSU) and 12 fragmented large subunit (LSU) rRNAs. Genome-wide comparative and evolutionary analyses showed cytb and cox3 to be the most and least conserved Eimeria PCGs, respectively, and placed E. zuernii more closely related to Eimeria mephitidis than other Eimeria species. Furthermore, cox1-based genetic structure defined 24 haplotypes of E. zuernii with high haplotype diversities and low nucleotide diversities across eight geographic populations, supporting a low genetic structure and rapid evolutionary rate as well as a previous expansion event among E. zuernii populations.

CONCLUSIONS

To our knowledge, this is the first study presenting the phylogeny, genetic diversity, and population structure of the yak E. zuernii, and such information, together with its mitogenomic data, should contribute to a better understanding of the genetic and evolutionary biological studies of apicomplexan parasites in bovines.

Endoparasite loads and the efficacy of conventional anthelmintics against gastrointestinal nematodes in captive European bison

Although little information exists on the efficacy of deworming in wild ruminants, gastrointestinal nematodes have been found to demonstrate increasing drug resistance. The spread of drug-resistant strains may be increased by transmission among livestock and susceptible wildlife species, thus posing a potential threat to endangered species, such as the European bison. The aim of the study was twofold: to identify the parasite loads in captive European bison with the use of coprological techniques, and to test the influence of other nearby ungulates on the richness of bison parasitofauna. Additionally, the efficacy of deworming procedures against gastrointestinal nematodes in bison was evaluated. The survey was based on a coprological investigation of 285 fecal samples from 156 European bison in 15 enclosures. The parasitofauna of the captive European bison was consistent with those of free-ranging populations. The highest prevalence was noted for Eimeria spp. oocysts (60.7%), strongyle eggs (50.9%), Fasciola hepatica eggs (13.1%), Dictyocaulus viviparus larvae (12.3%) and Trichuris sp. Eggs (9.47%). Moreover, the close proximity of other ungulate species resulted in a higher diversity of parasite species. In all cases, deworming with albendazole, fenbendazole and ivermectin proved to be ineffective against strongylids and Trichuris sp. The results of fecal egg count reduction test (FECRT) ranged from 37.2 to 99.6% (95% CI <90%) for albendazole; values >95% (95% CI = 41-100) were noted for fenbendazole, and FECRT ranged from 63.2 to 97.5 (95% CI = 0-99) for ivermectin. As the results of anthelmintic treatment are unsatisfactory, it seems justified to continue study in this area. Our study is the first large-scale attempt to evaluate the efficacy of anthelminthics in captive European bison. The potential sharing of parasite species between bison and other ungulates should also be further investigated from the perspective of minimizing the risk of the spread of drug-resistant parasite strains.

Two centrifugal flotation techniques for counting gastrointestinal parasite eggs and oocysts in alpaca faeces

Introduction

The alpaca (Vicugna pacos) is a camelid native to South America, but the species has wide distribution outside its natural habitat and is found in various countries on other continents, Poland being one in Europe. Parasitic infections affect the productivity and health of alpacas. The aim of the study was to estimate the parasite loads in alpacas kept in Poland with the use of two direct centrifugal flotation methods.

Material and Methods

A total of 248 faecal samples from alpacas from 12 provinces in Poland were examined for parasite eggs and oocysts with a modified Willis method (WM), and 59 samples were examined simultaneously with WM and a modified Stoll method (SM).

Results

The WM detected eggs of Trichostrongylidae, and the SM oocysts of Eimeria spp. as the respective most prevalent parasite material. The eggs of Nematodirus sp., Nematodirus battus, Aonchotheca sp., and Trichuris sp. were detected in lower numbers in both methods. Oocysts of E. macusaniensis and eggs of Moniezia sp. were the rarest in WM, the former also being so in SM; eggs of Moniezia were absent in SM. The prevalence of Eimeria spp. was significantly higher as detected by SM than as detected by WM; however, the prevalence of eggs of Nematodirus spp. and trichostrongyles was significantly higher as detected by WM than as detected by SM.

Conclusion

WM is more accurate at detecting heavy gastro-intestinal nematode eggs, including those of trichostrongyles and Nematodirus, whereas SM is more accurate at detecting smaller coccidia from the genus Eimeria.

Eimeria infections in domestic and wild ruminants with reference to control options in domestic ruminants

Eimeria infections are commonly seen in a variety of mammalian hosts. This genus of unicellular sporozoan parasites causes significant disease (coccidiosis) in different livestock species leading to economic losses for agricultural producers. Especially the production of cattle, sheep, and goat is strongly dependent on efficient coccidiosis control. However, many other livestock hosts like, e.g., camelids, bison, rabbits, and guinea pigs may benefit from reduced parasite transmission and targeted control measures as well. Besides livestock, also wildlife and pet animals may be affected by Eimeria infections resulting in clinical or subclinical coccidiosis. Wildlife herd health is crucial to conservation efforts, and Eimeria species are a prevalent pathogen in multiple mammalian wildlife species. This review aims to highlight the epidemiology of mammalian Eimeria infections in both wild and domestic ruminants, including host specificity, transmission, survival of environmental oocysts, occurrence, and risk factors for infection. Understanding general drivers of Eimeria infection may support adequate livestock and wildlife management. Furthermore, control options for livestock with reference to management factors, drug application, and alternative approaches are discussed. The goal of Eimeria control should be to reduce pathogen transmission in different host species and to improve sustainable livestock production. Controlling Eimeria infections in livestock is important considering both their animal welfare impact and their high economic relevance.

Development of a multiplex polymerase chain reaction technique for detection and discrimination of Eimeria spp. in cattle in Indonesia

Background and Aim: Bovine eimeriosis is a disease caused by apicomplexan parasites of the genus Eimeria. It is one of the most important and widespread bovine illnesses in the world. Some of the identified species of bovine eimeriosis have morphologically similar oocysts that are difficult to differentiate. For the identification of particular Eimeria spp., diagnostic laboratories are increasingly turning to DNA-based technology. This study aims to develop a multiplex polymerase chain reaction (mPCR) technique based on the internal transcribed spacer-1 (ITS-1) gene for the simultaneous identification of pathogenic Eimeria spp. in cattle from Sulawesi Island, Indonesia. Materials and Methods: Genomic DNA was extracted by the DNAzol reagent from the purified Eimeria oocysts. Species-specific primers targeting the ITS-1 region were used to amplify the distinct Eimeria spp. Results: Using PCR ITS-1, this study showed that 36 of 120 fecal samples (30%) were infected by Eimeria spp. The multiplex PCR assay allowed for the simultaneous identification of six major Eimeria spp. in a single-tube reaction. The proportion of mixed Eimeria spp. infections was 100% (36/36). The maximum number of Eimeria spp. was five, and the minimum number was two. Conclusion: Identification of six pathogenic Eimeria spp. in cattle was successfully carried out by nested multiplex PCR using ITS-1 gene. In the future, a procedure to detect pathogenic Eimeria spp. in one tube reaction will offer economical and save diagnostic time.

Veterinary monitoring of gastrointestinal parasites in European bison, Bison bonasus designated for translocation: Comparison of two coprological methods

It is important to monitor the level of parasitic loads in herds of European bison and to identify threats early enough to prevent their spread to other populations or species. The aim of the present study was to compare the detection sensitivity of two fecal flotation techniques, viz. the modified Willis method (WM) with centrifugation and modified McMaster flotation technique (MM), in the diagnostics of gastrointestinal parasites of European bison before the translocation of animals.

Out of 166 feces samples, Eimeria spp. oocysts (84.3% in WM and 71.1% in MM) and Trichostrongylidae eggs (82.5% in WM and 53.6% in MM) predominated. These were accompanied by eggs from Capillaria spp. (prevalence: 13.9% in WM and 3.61% in MM), Nematodirus spp. (prevalence: 18.1% in WM and 4.8% in MM) and Trichuris spp. (prevalence: 12.7% in WM and MM) were identified. The lowest prevalence was noted for cestode eggs of Moniezia spp. (5.4% in WM and 3.0% in MM).

The Willis method yielded a higher prevalence of eggs and oocysts than the modified McMaster method, and hence has a higher probability of detecting parasitic structures than the modified McMaster method, especially in cases of very low levels of invasion.

As the two methods yield consistent results, it is recommended to use the Willis method for diagnosis of internal parasite infection in European bison. This test offers more sensitive method than McMaster technique of detecting the presence of low levels of a variety of parasite eggs and oocysts in feces, while also being inexpensive and adaptable to field work.

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Methods yield similar relative prevalence.

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Higher prevalence of eggs/oocysts in Willis than McMaster.

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Very low prevalence may not be detected by the McMaster method.

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Proposed formulas are provided for converting prevalence between methods.

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The Willis method is recommended over the McMaster method.

The strong influence of management factors on coccidian infections in smallholder pig farms and the first molecular identification of Cystoisospora suis in Myanmar

A cross-sectional study was conducted to investigate coccidian infection and associated factors in smallholder pigs, and to identify Cystoisospora oocysts by PCR. A total of 500 pig faecal samples from 330 smallholder farms were collected in Nay Pyi Taw, Myanmar. The faecal flotation method was used to identify Eimeria and Cystoisospora species, and oocyst counts per gram (OPG) of faeces were recorded. Oocysts were differentiated after sporulation. Oocyst DNA was subjected to ITS1-targeted Cystoisospora-specific PCR. The overall coccidian oocyst detection rate by microscopic was 89.0% (445/500). Among the studied samples, 74.0% (370/500) and 70.6% (353/500), were found to be positive with Eimeria spp. and Cystoisospora suis oocysts, respectively. The sequences of C. suis detected were 100% identical to those of C. suis reported from Japan, and had 99.5% resemblance to sequences from Australia and China. Weaner pigs showed the significantly highest (p < 0.05) OPG when compared to other age groups. The highest intensity of coccidian infection (p < 0.05) was found in pigs fed local feed, pigs raised on earthen floors and pigs under poor hygienic conditions. Factors such as age, breed, feed type, and housing floors were found to be significantly associated with coccidian infection (p < 0.05). Age, as well as management factors including floor type, feed type, and hygiene practices on the farm, had a strong influence on the occurrence of coccidian infection in pigs. This is the first study in Myanmar on coccidian infection in pigs and molecular detection of C. suis.

Identification and characterization of Eimeria spp. in western north American Bison (Bison bison) herds and potential risk of cross-species transmission

The American bison (Bison bison) is an iconic native wildlife species of the Great Plains of North America. Recently, farmed bison have also gained importance to the livestock industry across the United States and Canada. One of the common diseases in young bison is coccidiosis, a diarrheal disease caused by protozoa that can result in significant morbidity. The goal of the present study was to investigate occurrence and identity of bison coccidia of the genus Eimeria in both farmed and free-ranging bison with focus on potential Eimeria species transmissibility between bison and cattle. Individual bison (up to one year of age) were sampled across Wyoming, Colorado, Nebraska, and South Dakota on six bison ranches (n = 137) and in two free-range herds (n = 70). Eimeria populations were assessed by fecal analyses. Morphological identification revealed presence of oocysts consistent with Eimeria (E.) bovis, E. zuernii, E. ellipsoidalis, E. cylindrica, E. alabamensis, E. auburnensis, E. canadensis, E. pellita, E. subspherica, and E. bukidnonensis, all of which are described in cattle. Additional Eimeria species specific ITS1 sequencing data along with generated phylogenetic maximum likelihood trees suggest that Eimeria species from cattle, namely E. bovis, E. zuernii, E. alabamensis, E. cylindrica, E. brasiliensis, E. ellipsoidalis, and E. wyomingensis, are genetically consistent with the detected bison coccidia. In conclusion, the study results indicate that bison harbor a variety of Eimeria species and bison Eimeria species appear to be transmissible between different bovine species such as bison and cattle.

Microscopic and molecular detection of Eimeria maxima and Eimeria praecox naturally infected in free-range village chickens of Myanmar

PURPOSE

In Myanmar, village chicken production is an important source of both income and food for rural households. The present study is aimed to conduct microscopic detection and molecular identification of Eimeria species in free-range village chickens in Myanmar.

METHODS

Faecal samples were taken from a total of 122 apparently healthy village chickens from three rural regions in Myanmar. The faecal samples were subjected to flotation method using a saturated sugar solution. Oocysts of Eimeria sp. were isolated by saturated sugar solution onto coverslips and identified to species at 400 × by light microscopy. Molecular identification was conducted for Eimeria oocysts collected from faecal samples using 18S rRNA and internal transcribed spacer-1 (ITS-1).

RESULTS

Eimeria oocysts were found in 41 samples (33.6%) by flotation method. Oocysts morphologically identified as E. maxima and E. praecox, were detected in 33 (27.0%) and 15 (12.3%) samples, respectively. Mixed infection of these two species was found in 7 (5.7%). Partial sequences of the 18S rRNA gene amplified from morphologically identified oocysts of E. maxima and E. praecox, revealed 99.9% and 100%, identities with the sequences of each species deposited in GenBank, respectively. Species-specific PCR of the ITS-1 region was also confirmed the presence of these two Eimeria species.

CONCLUSION

The results demonstrated the presence of E. maxima and E. praecox in free-range village chickens in Myanmar.

Stress hormone level and the welfare of captive European bison (Bison bonasus): the effects of visitor pressure and the social structure of herds

Background

Captive European bison (Bison bonasus) play an active role in conservation measures for this species; this includes education, which may conflict with these animals’ welfare. The effect of the presence of visitors on the welfare of captive animals can be negative, positive or neutral. However, the response of a given species to visitors is difficult to predict, since even closely related species display varying levels of tolerance to captivity. The aim of the study was to compare immunoreactive fecal cortisol levels (regarded as an indicator of the level of physiological stress) in groups of captive European bison that differed in terms of their social structure and the level of visitor pressure. The second aim was to determine if there was a correlation between intestinal parasitic burden and immunoreactive fecal cortisol levels.

Results

Immunoreactive fecal cortisol levels were not influenced by sex or age. However, study site and the interaction between study site and visitor pressure were statistically significant. European bison in one enclosure presented higher levels of immunoreactive fecal cortisol on weekdays than at weekends. In the other two study sites, the levels did not differ between weekdays and weekends. No correlation was found between parasitological infestation and immunoreactive fecal cortisol levels.

Conclusions

Measurement of fecal cortisol metabolites could be a valuable method for further research into the welfare of European bison in captivity. More subtle factors such as individual animal characteristics, feeding systems, and the arrangement of enclosures can be of great importance in terms of the effect of visitors on animals. The results of this study can be used in guidelines for the management of European bison populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13028-021-00589-9.

Essential differences in the mineral status of free-ranging European bison Bison bonasus populations in Poland: The effect of the anthroposphere and lithosphere

Tracking the concentration of elements in the organs of endangered animal species can provide significant knowledge about environmental hazards and allows more targeted protective measures to be taken. In this paper the differences in concentrations of 27 elements in the livers of free-ranging European bison were studied. The ICP-OES method was applied to study the four main Polish populations, which live in lowland (Białowieska, Knyszyńska and Borecka forests) and mountain (Bieszczady) habitats. The study was based on a unique and relatively large amount of comparative material. It was found that European bison populations that live in different locations differ from each other in terms of the hepatic concentrations of 17 of the elements studied in this work. The mountain population in Bieszczady was most distinctive due to the higher concentrations of Ba, Ca, Cd, Se, and the lower concentrations of Mo and V (compared to the other populations). Additionally, even geographically close lowland populations sometimes have different hepatic concentrations of particular elements. The sex and age of individuals have a weak effect on mineral status. Although the lithosphere is the primary factor that affects the availability of elements for the European bison, the soil parameters and biosphere can significantly affect the availability of elements, e.g. by accumulation. It was also shown that the anthroposphere plays a role, but this is mainly through agriculture as feeding on arable fields significantly changes the mineral status of European bison. The need for further research, especially on Cd, Se and Cu, was indicated. It was concluded that toxic elements or deficiencies in essential elements in the populations of the studied species should be considered locally as this would allow better understanding of the health condition of individual populations.

Gastrointestinal parasites of a reintroduced semi-wild plains bison (Bison bison bison) herd: Examining effects of demographic variation, deworming treatments, and management strategy

Bison (Bison spp) are being reintroduced into semi-wild, spatially constrained herds across North America and Europe. Herd managers are concerned about gastrointestinal (GI) nematode parasites as they care for the health of their bison. We examine how demographics, grazing location, herd management, and anthelmintic treatments affect the fecal egg counts (FECs) of GI nematodes within a reintroduced Plains bison (Bison bison bison) herd in the Great Plains. Our results suggest that younger bison (<2 years of age) experience higher GI parasite eggs/oocysts per gram (epg/opg) and that some taxa are more prevalent throughout different periods of a bison's early years. Demographic findings suggest that calf and yearling (0–2 yrs age) bison have the highest FECs and that these decline until reaching a low in peak adulthood and thereafter (x > 6 yrs of age). FECs of both Trichuris spp. and particularly Nematodirus spp. were much more abundant, relatively, during the first year of a bison's life. This pattern was also true of Moniezia spp. and Eimeria spp., however, strongyle-type spp. FECs appeared to peak in relative abundance during the second year of life. Our data also indicate that FECs are influenced by differences in land-use histories of pastures previously grazed by cattle or by the proportion of frequent flooding in different pastures. Treatment results suggest that fenbendazole may more effective than moxidectin at lowering FECs of bison over the long-term, and lasting effects of at least one administered anthelmintic treatment. Multiplex PCR assays revealed that American bison share GI nematodes with cattle including: Ostertagia spp., Haemonchus placei, Cooperia onchophora, and Oesophagostomum spp, but did not detect the presence Trichostrongylus columbriformis. Our results may have wider conservation implications for reintroduction efforts of American bison, as well as the endangered European bison (Bison bonasus).

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Younger plains bison (<2 years of age) are more likely to have higher fecal egg counts of gastrointestinal nematodes.

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Eimeria spp., Trichuris spp., Moniezia spp., and Nematodirus spp. are more prevalent in plains bison between zero and 1 years of age, while strongyle-type nematodes are more prevalent in bison between 1 and 2 years of age.

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Both land-use histories and landscape features may influence higher fecal egg counts of gastrointestinal nematodes in plains bison.

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Plains bison share many of the same type of gastrointestinal parasites found in cattle.

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Fenbendazole anthelmintic was more effective than moxidectin treatments in reducing fecal egg counts of gastrointestinal parasites in plains bison.

Usefulness of PCR-RFLP of 18S rRNA gene for rapid post-mortem diagnostics of highly pathogenic Eimeria spp. (Apicomplexa: Eimeriidae) of European bison, Bison bonasus L. with histopathological correlation

Eimeria spp. infection was investigated in 10 free-roaming European bison aged three months to 26 years by anatomopathological, histopathological, coproscopic and PCR-RFLP examination. The coproscopic study identified Eimeria oocysts in the faeces of five bison. The most prevalent morphotypes were E. bovis, present in all positive samples, and E. zuernii, in all but one. Additionally, mixed infections consisting of E. bovis, E. zuernii, E. alabamensis, E. auburnensis, E. canadensis, E. cylindrica, E. ellipsoidalis and E. subspherica were diagnosed in two bison calves. Besides being the most prevalent form, E. bovis also demonstrated the highest OPG (2,750). The presence of oocysts in the faeces was associated with those of macrogamonts, microgamonts and oocysts in the epithelium of the large intestine. Intestinal coccidiosis associated with lymphoplasmacytic enteritis was observed in many bison, not only those with positive OPG. Four animals with negative coproscopy results demonstrated early-stage gametogony in the large intestine; one case presented no endogenous stages of coccidians in the histopathological sections of the intestine, nor oocysts in the faecal samples. A 530 bp product of E. bovis 18S rDNA (GenBank: MK951685) was obtained from both the colon wall and oocysts; this was subjected to PCR-RFLP analysis based on AluI and Hin1II (NlaIII) restriction enzymes. Both samples yielded a consistent seven-band pattern, four of which (270 bp, 40 bp, 180 bp and 84 bp) were expected, and the other three represented undigested fragments. The obtained digestion pattern is indicative of Eimeria spp. infection, and can serve as a first-step diagnostic approach in detection of infection. The result of computer-based virtual digestion of the PCR product suggests that double digestion with Mval (BstNI) and KpnI restriction enzymes may be used as a second-step tool to distinguish between E. bovis, E. zuernii and E. alabamensis, all of which are highly-pathogenic species.

Ruminant Coccidiosis

Ruminant coccidiosis, caused by Eimeria species, is a significant and widespread enteric disease in young livestock worldwide. High morbidities and significant mortalities may be observed. For disease diagnosis, fecal samples from clinically ill animals should be analyzed for both, identity (ie, pathogenicity) of Eimeria species and excreted oocyst amount. To prevent coccidiosis-related economic losses, management measures to reduce infection pressure and improve general animal health are crucial. Anticoccidial drugs are widely used to control clinical and subclinical disease. Treatment is most efficient when applied prophylactically or metaphylactically. To avoid development of parasite drug resistance, drugs should be used sustainably.