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Rendle D, Hughes K, Bowen M, Bull K, Cameron I, Furtado T, Peachey L, Sharpe L, Hodgkinson J. BEVA primary care clinical guidelines: Equine parasite control. Equine Vet J 2024; 56:392-423. [PMID: 38169127 DOI: 10.1111/evj.14036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 11/16/2023] [Indexed: 01/05/2024]
Abstract
BACKGROUND There is a lack of consensus on how best to balance our need to minimise the risk of parasite-associated disease in the individual horse, with the need to limit the use of anthelmintics in the population to preserve their efficacy through delaying further development of resistance. OBJECTIVES To develop evidence-based guidelines utilising a modified GRADE framework. METHODS A panel of veterinary scientists with relevant expertise and experience was convened. Relevant research questions were identified and developed with associated search terms being defined. Evidence in the veterinary literature was evaluated using the GRADE evidence-to-decision framework. Literature searches were performed utilising CAB abstracts and PubMed. Where there was insufficient evidence to answer the research question the panel developed practical guidance based on their collective knowledge and experience. RESULTS Search results are presented, and recommendation or practical guidance were made in response to 37 clinically relevant questions relating to the use of anthelmintics in horses. MAIN LIMITATIONS There was insufficient evidence to answer many of the questions with any degree of certainty and practical guidance frequently had to be based upon extrapolation of relevant information and the panel members' collective experience and opinions. CONCLUSIONS Equine parasite control practices and current recommendations have a weak evidence base. These guidelines highlight changes in equine parasite control that should be considered to reduce the threat of parasite-associated disease and delay the development of further anthelmintic resistance.
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Affiliation(s)
| | - Kristopher Hughes
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Mark Bowen
- Medicine Vet Referrals, Nottinghamshire, UK
| | - Katie Bull
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | | | - Tamzin Furtado
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, UK
| | - Laura Peachey
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | | | - Jane Hodgkinson
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, UK
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Walshe N, Mulcahy G, Crispie F, Cabrera-Rubio R, Cotter P, Jahns H, Duggan V. Outbreak of acute larval cyathostominosis - A "perfect storm" of inflammation and dysbiosis. Equine Vet J 2020; 53:727-739. [PMID: 32920897 PMCID: PMC8246859 DOI: 10.1111/evj.13350] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/29/2020] [Accepted: 08/29/2020] [Indexed: 12/13/2022]
Abstract
Background Cyathostomins are prevalent and pathogenic intestinal helminths of horses, causing acute and chronic disease, including acute larval cyathostominosis, which has a mortality rate of 50%. Factors determining individual susceptibility to acute larval cyathostominosis are unknown. Investigation of these factors could lead to novel treatment and prevention strategies. Objectives To investigate clinicopathological and faecal microbiota changes associated with disease in individual horses in an acute larval cyathostominosis outbreak. Study design Case series. Methods The study population was a herd of 23 mixed breed horses in Ireland. The outbreak occurred in November 2018. Fourteen horses were clinically affected. Clinical status was monitored and recorded. Blood and faecal sampling allowed clinicopathological, faecal 16s rRNA gene sequencing and faecal egg count analyses. Results Two horses were euthanised, whilst 12 recovered. Common clinical signs included loose faecal consistency, weight loss and pyrexia. Consistent clinicopathological findings were borderline anaemia, leucocytosis, thrombocytosis, hyperfibrinogenaemia, hyperglobulinaemia and a reverse A: G ratio. Decreased alpha‐diversity of the faecal microbiota and greater relative abundance of the genus Streptococcus, class Bacilli, order Lactobacillales and family Streptococcaceae, and family Prevotelleceae was found in clinically affected horses compared to their clinically normal cohorts. An increase in obligate fibrolytic bacteria was seen in the clinically normal group compared to the clinical group. Histopathological findings of the colon and caecum revealed a severe necrotising typhlocolitis associated with cyathostomin larvae and bacterial overgrowth in the mucosa of the large intestine. Main limitations The study population in this outbreak is small. There are several confounding factors limiting this to a descriptive case series. Faecal microbiota has been shown to reflect the large intestinal microbiota but do not represent changes directly. Conclusions These findings suggest that acute larval cyathostominosis is associated with dysbiosis of the gut microbiota as well as the inflammatory stimulus of numerous emerging larvae leading to structural and functional pathology of the large intestine.
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Affiliation(s)
- Nicola Walshe
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Grace Mulcahy
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland.,Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Dublin, Ireland
| | - Fiona Crispie
- Teagasc Food Research Centre, APC Microbiome, Moorepark, Ireland.,APC Microbiome Ireland, Moorepark, Ireland
| | | | - Paul Cotter
- Teagasc Food Research Centre, APC Microbiome, Moorepark, Ireland.,APC Microbiome Ireland, Moorepark, Ireland.,Vistamilk, Moorepark, Ireland
| | - Hanne Jahns
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Vivienne Duggan
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
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3
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Walshe N, Duggan V, Cabrera-Rubio R, Crispie F, Cotter P, Feehan O, Mulcahy G. Removal of adult cyathostomins alters faecal microbiota and promotes an inflammatory phenotype in horses. Int J Parasitol 2019; 49:489-500. [PMID: 30986403 DOI: 10.1016/j.ijpara.2019.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/13/2019] [Accepted: 02/24/2019] [Indexed: 12/19/2022]
Abstract
The interactions between parasitic helminths and gut microbiota are considered to be an important, although as yet incompletely understood, factor in the regulation of immunity, inflammation and a range of diseases. Infection with intestinal helminths is ubiquitous in grazing horses, with cyathostomins (about 50 species of which are recorded) predominating. Consequences of infection include both chronic effects, and an acute inflammatory syndrome, acute larval cyathostominosis, which sometimes follows removal of adult helminths by administration of anthelmintic drugs. The presence of cyathostomins as a resident helminth population of the equine gut (the "helminthome") provides an opportunity to investigate the effect helminth infection, and its perturbation, has on both the immune system and bacterial microbiome of the gut, as well as to determine the specific mechanisms of pathophysiology involved in equine acute larval cyathostominosis. We studied changes in the faecal microbiota of two groups of horses following treatment with anthelmintics (fenbendazole or moxidectin). We found decreases in both alpha diversity and beta diversity of the faecal microbiota at Day 7 post-treatment, which were reversed by Day 14. These changes were accompanied by increases in inflammatory biomarkers. The general pattern of faecal microbiota detected was similar to that seen in the relatively few equine gut microbiome studies reported to date. We conclude that interplay between resident cyathostomin populations and the bacterial microbiota of the equine large intestine is important in maintaining homeostasis and that disturbance of this ecology can lead to gut dysbiosis and play a role in the aetiology of inflammatory conditions in the horse, including acute larval cyathostominosis.
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Affiliation(s)
- Nicola Walshe
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin, Ireland
| | - Vivienne Duggan
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin, Ireland
| | - Raul Cabrera-Rubio
- Teagasc Food Research Centre, Moorepark, Fermoy, APC Microbiome, Ireland
| | - Fiona Crispie
- Teagasc Food Research Centre, Moorepark, Fermoy, APC Microbiome, Ireland
| | - Paul Cotter
- Teagasc Food Research Centre, Moorepark, Fermoy, APC Microbiome, Ireland
| | - Orna Feehan
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin, Ireland
| | - Grace Mulcahy
- School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin, Ireland.
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New insights into sequence variation in the IGS region of 21 cyathostomin species and the implication for molecular identification. Parasitology 2012; 139:1063-73. [DOI: 10.1017/s0031182012000467] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYCyathostomins comprise a group of 50 species of parasitic nematodes that infect equids. Ribosomal DNA sequences, in particular the intergenic spacer (IGS) region, have been utilized via several methodologies to identify pre-parasitic stages of the commonest species that affect horses. These methods rely on the availability of accurate sequence information for each species, as well as detailed knowledge of the levels of intra- and inter-specific variation. Here, the IGS DNA region was amplified and sequenced from 10 cyathostomin species for which sequence was not previously available. Also, additional IGS DNA sequences were generated from individual worms of 8 species already studied. Comparative analysis of these sequences revealed a greater range of intra-specific variation than previously reported (up to 23%); whilst the level of inter-specific variation (3–62%) was similar to that identified in earlier studies. The reverse line blot (RLB) method has been used to exploit the cyathostomin IGS DNA region for species identification. Here, we report validation of novel and existing DNA probes for identification of cyathostomins using this method and highlight their application in differentiating life-cycle stages such as third-stage larvae that cannot be identified to species by morphological means†.
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5
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Illustrated identification keys to strongylid parasites (strongylidae: Nematoda) of horses, zebras and asses (Equidae). Vet Parasitol 2008; 156:4-161. [PMID: 18603375 DOI: 10.1016/j.vetpar.2008.04.026] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Revised: 04/16/2008] [Accepted: 04/21/2008] [Indexed: 11/22/2022]
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Infectious and Parasitic Diseases of the Alimentary Tract. JUBB, KENNEDY & PALMER'S PATHOLOGY OF DOMESTIC ANIMALS 2007. [PMCID: PMC7155580 DOI: 10.1016/b978-070202823-6.50096-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Abstract
The results of the treatment with moxidectin or ivermectin of 20 horses with clinical cyathostominosis were studied during a 3-week observation period. Both treatments were effective in completely eliminating larvae from the faeces within 1 or 2 weeks, but no significant improvement in body weight or clinical parameters could be demonstrated over the observation period. The poor short time results of the treatment support the need for an adequate prevention of cyathostominosis in horses.
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Affiliation(s)
- P Deprez
- Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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Dowdall SMJ, Proudman CJ, Klei TR, Mair T, Matthews JB. Characterisation of IgG(T) serum antibody responses to two larval antigen complexes in horses naturally- or experimentally-infected with cyathostomins. Int J Parasitol 2004; 34:101-8. [PMID: 14711595 DOI: 10.1016/j.ijpara.2003.09.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cyathostomins are the most common parasitic nematodes of horses. Larval stages, which inhabit the intestinal wall, are particularly pathogenic and can cause severe colitis and colic. Despite their clinical importance, diagnostic techniques for the prepatent stages do not exist. A method that could estimate mucosal infection intensity would have a major impact on the control and diagnosis of cyathostominosis. Here, serum IgG(T) responses to two larval antigen complexes of 25 and 20 kDa were quantified in horses with experimental infections, natural infections and in horses that presented with clinical larval cyathostominosis. In experimentally-infected animals, anti-25 kDa complex IgG(T) levels correlated positively with field exposure and with early third stage larval (r(s)=0.74, P=0.015) and total mucosal parasite (r(s)=0.78, P=0.010) burdens. In naturally exposed horses whose parasite burdens were quantified upon post-mortem examination, antigen-specific IgG(T) responses were significantly higher in infected than in uninfected horses (P=0.0001 and 0.002, for anti-25 and anti-20 kDa responses, respectively). In these animals, anti-25 kDa IgG(T) levels correlated positively with mucosal and lumenal burdens (P<0.05). IgG(T) responses to the 20 kDa antigen complex correlated positively with lumenal burdens (P=0.0043). In cases of larval cyathostominosis, antigen-specific IgG(T) levels were significantly higher than in uninfected ponies (P=0.002 and 0.0035, for anti-25 and anti-20 kDa responses, respectively). These results provide evidence that these two complexes contain antigens with potential as markers for prepatent cyathostomin infection.
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Affiliation(s)
- Samantha M J Dowdall
- Department of Veterinary Clinical Science, Faculty of Veterinary Science, University of Liverpool, Leahurst, South Wirral CH64 7TE, UK.
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Lichtenfels JR, Gibbons LM, Krecek RC. Recommended terminology and advances in the systematics of the Cyathostominea (Nematoda: Strongyloidea) of horses. Vet Parasitol 2002; 107:337-42. [PMID: 12163244 DOI: 10.1016/s0304-4017(02)00167-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Terminology for common names for the Tribe Cyathostominea (cyathostomins), and disease caused by the nematodes (cyathostominosis), were recommended to replace the previously used names cyathostomes and cyathostomosis, which are ambiguous, inaccurate or synonymous, by the Third Internal Workshop on the Systematics of Cyathostominea of Horses, held in Stresa, Italy, 28 August 2001. The progress by this international working group at three workshops is reviewed briefly and a list of publications is provided. Included are an annotated checklist by genus and species of 93 species level names and the recognition of 52 species, redescriptions of seven species, and the description of one new species. Upon petition by workshop participants, the International Commission on Zoological Nomenclature placed Cyathostomum tetracanthum Mehlis, 1831 on the "Official List of Specific Names in Zoology", ending more than a century of controversy over the names of cyathostomins. Some progress is described in molecular and morphological systematics and in the development of diagnostic molecular probes. A revised identification key is being prepared to the 52 species of the Tribe Cyathostominea.
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Affiliation(s)
- J R Lichtenfels
- Parasite Biology, Epidemiology and Systematics Laboratory, Agricultural Research Service, US Department of Agriculture, The Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, MD 20705-2350, USA.
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Hodgkinson JE, Love S, Lichtenfels JR, Palfreman S, Ramsey YH, Matthews JB. Evaluation of the specificity of five oligoprobes for identification of cyathostomin species from horses. Int J Parasitol 2001; 31:197-204. [PMID: 11239940 DOI: 10.1016/s0020-7519(00)00161-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Here, we report evaluation of five oligoprobes designed from intergenic spacer (IGS) region sequences for identification of cyathostomin species. Oligoprobes were designed for identification of Cylicocyclus ashworthi, Cylicocyclus nassatus, Cylicostephanus longibursatus, Cylicostephanus goldi and a fifth probe designed to identify all members of this tribe. PCR amplification of IGS DNA from 16 cyathostomin species allowed sequence comparison and identification of four putative species-specific probes. Southern blotting of amplified products from 16 species showed that all probes were species-specific. The fifth probe recognised all 16 cyathostomin species but did not bind to members of the genus Strongylus. Furthermore, these probes were used to identify individual infective L3, eggs and L4 indicating that they will be invaluable to furthering the study of the epidemiology and pathogenesis of these important equine nematodes.
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Affiliation(s)
- J E Hodgkinson
- Division of Equine Studies, Department of Veterinary Clinical Sciences and Animal Husbandry, University of Liverpool, Leahurst, South, CH64 7TE, Wirral, UK.
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Abstract
Over the past few years, cyathostomiasis has become increasingly recognized as a clinical problem of horses in the United States. Clinical cyathostomiasis has been reported frequently in Europe for a considerable time. This clinical syndrome is usually related to the sudden release of large numbers of the larval stages of small strongyles from the mucosa of the large intestine. Typical clinical signs include diarrhea, ventral abdominal edema, pyrexia, colic, weight loss, and poor body condition. Hypoalbuminemia and the presence of large numbers of small strongyles being passed in the feces are also characteristic features of the disease. The disease may occur seasonally in late winter and early spring or after drug treatment to remove the luminal stages of small strongyles. Two commercially available drugs, moxidectin and fenbendazole, have been shown to be effective against the encysted larval stages of the parasites. Drug resistance of small strongyles to all classes of currently available antiparasitic compounds except the macrocyclic lactones (ivermectin and moxidectin) is a limiting factor in controlling these parasites and may result in an increased prevalence of clinical cyathostomiasis over time.
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Affiliation(s)
- E T Lyons
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, USA
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13
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Eysker M, Klei TR. Mucosal larval recovery techniques of cyathostomes: can they be standardized? Vet Parasitol 1999; 85:137-44; discussion 145-9, 215-25. [PMID: 10485360 DOI: 10.1016/s0304-4017(99)00094-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The methods used currently for enumeration of mucosal stages of cyathostomes include transmural illumination (TMI) and peptic digestion (DIG). Enumerating the inhibited early L3 (EL3) and differentiating between mucosal developing L3 (DL3) and L4 (ML4) is only possible when DIG is used. However, in some studies higher numbers of DL (DL3 + ML4) have been found when using TMI as opposed to DIG. This finding, however, is not consistent. Moreover, results are not consistent when DIG and TMI are compared for treated and control groups of horses in drug trials. Studies performed on the effect of freezing on DIG and TMI also show inconsistent results between laboratories. However, there is, evidence that digested samples can be preserved in 5-10% formalin or in 70% ethanol when used as a buffered isotonic solution. Based on these results it is premature to recommend standardized mucosal larval recovery techniques. Consequently, TMI and DIG should both be applied. Recommendations for further research for the development of standardized techniques are given.
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Affiliation(s)
- M Eysker
- Department of Parasitology and Tropical Veterinary Medicine, Utrecht University, The Netherlands.
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Lichtenfels JR, Kharchenko VA, Krecek RC, Gibbons LM. An annotated checklist by genus and species of 93 species level names for 51 recognized species of small strongyles (Nematoda: Strongyloidea: Cyathostominea) of horses, asses and zebras of the world. Vet Parasitol 1998; 79:65-79. [PMID: 9777726 DOI: 10.1016/s0304-4017(98)00149-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The results of an international collaborative effort to prepare a recommended list of scientific names for the small strongyles (Nematoda: Strongyloidea: Cyathostominea) of horses, donkeys and zebras are reported. Fifty-one valid species are recognized in 13 genera, including Cyathostomum, Coronocyclus, Cylicodontophorus, Cylicocyclus, Cylicostephanus, Skrjabinodentus, Tridentoinfundibulum, Petrovinema, Poteriostomum, Parapoteriostomum, Hsiungia, Cylindropharynx and Caballonema. In addition, 42 other species level names are listed as synonyms of the 51 recognized species or as species inquirendae (10 species) or nomen nudum (one species). Numerous annotations provide information on the nomenclatural and systematics history, current status and additional studies needed.
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Affiliation(s)
- J R Lichtenfels
- Biosystematics and National Parasite Collection Unit, Livestock and Poultry Sciences Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705-2350, USA.
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