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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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Cai E, Wu R, Wu Y, Gao Y, Zhu Y, Li J. A systematic review and meta-analysis on the current status of anthelmintic resistance in equine nematodes: A global perspective. Mol Biochem Parasitol 2024; 257:111600. [PMID: 38030084 DOI: 10.1016/j.molbiopara.2023.111600] [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: 03/31/2023] [Revised: 11/22/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023]
Abstract
BACKGROUND The intensive application of anthelmintics in equine has led to considerable resistance in cyathostomins and Parascaris equorum. It has been well documented that benzimidazole (BZ) and pyrantel resistance is widespread in cyathostomins and Parascaris equorum. Since no new classes of anthelmintic have been introduced in the last 40 years, it is critical to be aware of the current risk factors of anthelmintic application to avoid further resistance. OBJECTIVE To review the factors affecting the level of anthelmintics resistance in equine around the world, type of anthelmintics, mode of application, dosage, nematode species, and location of anthelmintics application were evaluated and summarized. DESIGN/PROCEDURE A systematic review and meta-analyses following the PRISMA Framework were conducted to identify, evaluate, and synthesize primary literature reporting the efficacy of anthelmintic drugs in equines. Information on the bibliographic data, anthelmintic drugs, animals, continents, parasite genera, type of anthelmintics, and dosage was collected. Nonparametric tests (Kruskal-Wallis and Mann-Whitney) were used in SPSS (v.27) to investigate the association between variables. Factors that have a significant impact on efficacy have been subjected to binary logistic regression. Six meta-analyses were conducted in Microsoft Excel (2021) to qualify current resistance issues of the three major anthelmintics classes. RESULTS The final database was composed of 60 articles published between 1994 and 2022 with a total of 11835 animals. Anthelmintic class as well as anthelmintic active principle selection did have a significant effect on resistance (P < 0.01), whilst no correlation of the type of anthelmintics, mode of application, and dosage with efficacy were found. Anthelmintics resistance in ascarid was significantly more severe than in strongyle (P < 0.01). Macrocyclic lactone (ML) class and the benzimidazole and probenzimidazole (BP) class have the lowest efficacy against ascarid and strongyle, respectively (67.83% and 69.85%). The effect of location (by continent) also had a significant influence on the resistance of the ML class (P < 0.01). The resistance of the BP class which is the most prevalently applied was demonstrated in all six continents. Binary logistic regression revealed that parasite genera and drug class independently influenced the presence of drug resistance. The forest plots included in this study did not show a significant difference over time. CONCLUSION Current evidence indicated that anthelmintics resistance of ML and BP class were common in ascarid and strongyle. A combination of anthelmintics may reduce anthelmintics resistance, but multi-drug resistance may be a concern. Customerised anthelmintics strategy could help reduce resistance.
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Affiliation(s)
- Enjia Cai
- Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Rongzheng Wu
- Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yuhong Wu
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, United States
| | - Yu Gao
- University of Veterinary Medicine Hannover Foundation, Hannover D-30559, Germany
| | - Yiping Zhu
- Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
| | - Jing Li
- Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
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Lejeune M, Mann S, White H, Maguire D, Hazard J, Young R, Stone C, Antczak D, Bowman D. Evaluation of Fecal Egg Count Tests for Effective Control of Equine Intestinal Strongyles. Pathogens 2023; 12:1283. [PMID: 38003748 PMCID: PMC10674696 DOI: 10.3390/pathogens12111283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 11/26/2023] Open
Abstract
The American Association of Equine Practitioners strongly advocates evidence-based intestinal strongyle control in horses. It recommends targeted treatment of all heavy egg shedders (>500 eggs per gram (EPG) of feces), while the low shedders (0-200 EPG) are left untreated. As 50-75% of adult horses in a herd are low shedders, preventing them from unnecessary anthelmintic exposure is critical for tackling resistance. There are various fecal egg count (FEC) techniques with many modifications and variations in use, but none is identified as a gold standard. The hypothesis of the study was that the diagnostic performance of 12 commonly used quantitation methodologies (three techniques with four variants) differs. In this regard, method comparison studies were performed using polystyrene beads as proxy for intestinal strongyle eggs. Mini-FLOTAC-based variants had the lowest coefficient of variation (CV%) in bead recovery, whereas McMaster variants had the highest. All four variants of Mini-FLOTAC and the NaNO3 1.33 specific gravity variant of modified Wisconsin followed a linear fit with R2 > 0.95. In contrast, the bead standard replicates for modified McMaster variants dispersed from the regression curve, causing a lower R2. The Mini-FLOTAC method seems less influenced by the choice of floatation solution and has better repeatability parameters and linearity for bead standard recovery. For FEC tests with high R2 (>0.95) but that underestimated the true bead count, a correction factor (CF) was determined to estimate the true count. Finally, the validity of CF was analyzed for 5 tests with R2 > 0.95 to accurately quantify intestinal strongyle eggs from 40 different horses. Overall, this study identified FEC methodologies with the highest diagnostic performance. The limitations in standardizing routine FEC tests are highlighted, and the importance of equalization of FEC results is emphasized for promoting uniformity in the implementation of parasite control guidelines.
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Affiliation(s)
- Manigandan Lejeune
- Animal Health Diagnostic Center, Department of Population Medicine and Diagnostic Sciences, Cornell University, 240 Farrier Rd., Ithaca, NY 14853, USA; (H.W.); (D.M.); (J.H.); (R.Y.)
| | - Sabine Mann
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA;
| | - Holly White
- Animal Health Diagnostic Center, Department of Population Medicine and Diagnostic Sciences, Cornell University, 240 Farrier Rd., Ithaca, NY 14853, USA; (H.W.); (D.M.); (J.H.); (R.Y.)
| | - Danielle Maguire
- Animal Health Diagnostic Center, Department of Population Medicine and Diagnostic Sciences, Cornell University, 240 Farrier Rd., Ithaca, NY 14853, USA; (H.W.); (D.M.); (J.H.); (R.Y.)
| | - Jaime Hazard
- Animal Health Diagnostic Center, Department of Population Medicine and Diagnostic Sciences, Cornell University, 240 Farrier Rd., Ithaca, NY 14853, USA; (H.W.); (D.M.); (J.H.); (R.Y.)
| | - Rebecca Young
- Animal Health Diagnostic Center, Department of Population Medicine and Diagnostic Sciences, Cornell University, 240 Farrier Rd., Ithaca, NY 14853, USA; (H.W.); (D.M.); (J.H.); (R.Y.)
| | - Charles Stone
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA;
| | - Doug Antczak
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA; (D.A.); (D.B.)
| | - Dwight Bowman
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA; (D.A.); (D.B.)
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Integrative biology defines novel biomarkers of resistance to strongylid infection in horses. Sci Rep 2021; 11:14278. [PMID: 34253752 PMCID: PMC8275762 DOI: 10.1038/s41598-021-93468-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/16/2021] [Indexed: 02/06/2023] Open
Abstract
The widespread failure of anthelmintic drugs against nematodes of veterinary interest requires novel control strategies. Selective treatment of the most susceptible individuals could reduce drug selection pressure but requires appropriate biomarkers of the intrinsic susceptibility potential. To date, this has been missing in livestock species. Here, we selected Welsh ponies with divergent intrinsic susceptibility (measured by their egg excretion levels) to cyathostomin infection and found that their divergence was sustained across a 10-year time window. Using this unique set of individuals, we monitored variations in their blood cell populations, plasma metabolites and faecal microbiota over a grazing season to isolate core differences between their respective responses under worm-free or natural infection conditions. Our analyses identified the concomitant rise in plasma phenylalanine level and faecal Prevotella abundance and the reduction in circulating monocyte counts as biomarkers of the need for drug treatment (egg excretion above 200 eggs/g). This biological signal was replicated in other independent populations. We also unravelled an immunometabolic network encompassing plasma beta-hydroxybutyrate level, short-chain fatty acid producing bacteria and circulating neutrophils that forms the discriminant baseline between susceptible and resistant individuals. Altogether our observations open new perspectives on the susceptibility of equids to strongylid infection and leave scope for both new biomarkers of infection and nutritional intervention.
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Wilkes EJA, Heller J, Raidal SL, Woodgate RG, Hughes KJ. A questionnaire study of parasite control in Thoroughbred and Standardbred horses in Australia. Equine Vet J 2020; 52:547-555. [PMID: 31725925 DOI: 10.1111/evj.13207] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 09/17/2019] [Accepted: 11/08/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Information regarding parasite control practices currently used on Thoroughbred and Standardbred studs in Australia is lacking. Anthelmintic resistance (AR) is a global problem which has implications for equine health and welfare. OBJECTIVES To identify parasite control practices currently used on horse studs in Australia and investigate the frequency of use of management factors that have been associated with the likelihood of promoting or delaying AR. STUDY DESIGN Questionnaire study of equine parasite control on Thoroughbred and Standardbred studs in Australia. METHODS An online questionnaire was emailed to 300 studs in Australia. Information obtained included property details, grazing management, anthelmintic use, non-chemotherapeutic parasite control practices, use of faecal egg counts (FECs) and perceptions of AR. RESULTS Seventy-five completed questionnaires were received (25% response rate). Macrocyclic lactones (MLs) were the most commonly administered anthelmintics in mares and foals and less than 5% of respondents used targeted treatment regimens. The implementation of pasture hygiene practices was variable. The majority of respondents (97%) considered AR to be important; however, few respondents were aware of the use of FEC reduction tests for monitoring of drug efficacy. MAIN LIMITATIONS The potential for nonresponse bias was the main limitation of this study. CONCLUSIONS Parasite control strategies on Australian stud farms remain over-reliant on anthelmintic use. The frequent use of MLs is of concern for the increased selection pressure for AR. There is a lack of awareness of the importance of non-chemotherapeutic strategies in integrated approaches to parasite control aimed at delaying the development of AR. This study highlights the need for greater veterinary involvement in the implementation of more sustainable parasite control practices with greater emphasis placed on surveillance through FEC testing.
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Affiliation(s)
- Edwina J A Wilkes
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Jane Heller
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Sharanne L Raidal
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Robert G Woodgate
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Kristopher J Hughes
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
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Horses grazing with cattle have reduced strongyle egg count due to the dilution effect and increased reliance on macrocyclic lactones in mixed farms. Animal 2019; 14:1076-1082. [PMID: 31679547 PMCID: PMC7163393 DOI: 10.1017/s1751731119002738] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Strongyle infection is an important issue in horse breeding. It impairs horse health and performance, with young horses being the most sensitive. Strongyle control has long relied on the systematic use of chemical treatments. However, expanding anthelmintic resistance among strongyles calls for alternative options. Mixed grazing is assumed to reduce strongyle load on the pasture as the result of a dilution effect. This has been shown in small ruminants grazing with cattle, but the putative benefits of co-grazing between horses and cattle have not yet been evaluated. Here, we conducted field surveys and face-to-face interviews on 44 farms from two contrasted saddle-horse production areas, Normandy and northern Massif Central, to compare equine strongyle management practices between specialized systems and mixed horse-cattle systems. Our goals were (i) to quantify breeders’ awareness of the putative benefits associated with the co-grazing of horses and cattle, (ii) to establish whether mixed farming was associated with different strongyle management strategies and (iii) to test whether strongyle egg excretion was reduced in horses grazed with beef cattle. Every breeder relied on systematic calendar treatments, and only 8 out of the 23 mixed breeders were aware that co-grazing of horses with cattle could be used as part of their strongyle control strategy. Management practices were similar across both systems in Normandy. In Massif Central, mixed breeders formed a distinct cluster from their specialized counterparts: deworming was less frequent and stocking density was higher in mixed farms, while specialized breeders seemed more willing to integrate herd and plot management into control strategies. Faecal egg counts measured in horses from Massif Central were significantly reduced when horses were grazed with cattle. This was the result of an increased reliance on macrocyclic lactones in mixed farms (P < 0.01) and a significant dilution effect (P < 0.01). When considering a subsample of horses treated with macrocyclic lactones only, young horses grazed with cattle had 50% fewer strongyle eggs excreted in their faeces than horses grazed in equine-only pastures (P < 0.01). This is the first evidence of the benefits of mixed grazing with cattle as an alternative to control strongyle infection in horses, although this promising alternative remains largely unknown by horse breeders.
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Rendle D, Austin C, Bowen M, Cameron I, Furtado T, Hodgkinson J, McGorum B, Matthews J. Equine de-worming: a consensus on current best practice. ACTA ACUST UNITED AC 2019. [DOI: 10.12968/ukve.2019.3.s.3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Mark Bowen
- Oakham Veterinary Hospital, Rutland / University of Nottingham
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Clark A, Sallé G, Ballan V, Reigner F, Meynadier A, Cortet J, Koch C, Riou M, Blanchard A, Mach N. Strongyle Infection and Gut Microbiota: Profiling of Resistant and Susceptible Horses Over a Grazing Season. Front Physiol 2018; 9:272. [PMID: 29618989 PMCID: PMC5871743 DOI: 10.3389/fphys.2018.00272] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/08/2018] [Indexed: 12/20/2022] Open
Abstract
Gastrointestinal strongyles are a major threat to horses' health and welfare. Given that strongyles inhabit the same niche as the gut microbiota, they may interact with each other. These beneficial or detrimental interactions are unknown in horses and could partly explain contrasted susceptibility to infection between individuals. To address these questions, an experimental pasture trial with 20 worm-free female Welsh ponies (10 susceptible (S) and 10 resistant (R) to parasite infection) was implemented for 5 months. Fecal egg counts (FEC), hematological and biochemical data, body weight and gut microbiological composition were studied in each individual after 0, 24, 43, 92 and 132 grazing days. R and S ponies displayed divergent immunological profiles and slight differences in microbiological composition under worm-free conditions. After exposure to natural infection, the predicted R ponies exhibited lower FEC after 92 and 132 grazing days, and maintained higher levels of circulating monocytes and eosinophils, while lymphocytosis persisted in S ponies. Although the overall gut microbiota diversity and structure remained similar during the parasite infection between the two groups, S ponies exhibited a reduction of bacteria such as Ruminococcus, Clostridium XIVa and members of the Lachnospiraceae family, which may have promoted a disruption of mucosal homeostasis at day 92. In line with this hypothesis, an increase in pathobionts such as Pseudomonas and Campylobacter together with changes in several predicted immunological pathways, including pathogen sensing, lipid metabolism, and activation of signal transduction that are critical for the regulation of immune system and energy homeostasis were observed in S relative to R ponies. Moreover, S ponies displayed an increase in protozoan concentrations at day 92, suggesting that strongyles and protozoa may contribute to each other's success in the equine intestines. It could also be that S individuals favor the increase of these carbohydrate-degrading microorganisms to enhance the supply of nutrients needed to fight strongyle infection. Overall, this study provides a foundation to better understand the mechanisms that underpin the relationship between equines and natural strongyle infection. The profiling of horse immune response and gut microbiota should contribute to the development of novel biomarkers for strongyle infection.
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Affiliation(s)
- Allison Clark
- Department of Health Science, Open University of Catalonia, Barcelona, Spain
| | - Guillaume Sallé
- UMR 1282, Institut National de la Recherche Agronomique, Infectiologie et Santé Publique, Université François-Rabelais, Nouzilly, France
| | - Valentine Ballan
- UMR 1313, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Fabrice Reigner
- UEPAO 1297, Institut National de la Recherche Agronomique, Unité Expérimentale de Physiologie Animale de l'Orfrasière, Nouzilly, France
| | - Annabelle Meynadier
- UMR 1388, Institut National de la Recherche Agronomique, GenPhySE, Toulouse, France
| | - Jacques Cortet
- UMR 1282, Institut National de la Recherche Agronomique, Infectiologie et Santé Publique, Université François-Rabelais, Nouzilly, France
| | - Christine Koch
- UMR 1282, Institut National de la Recherche Agronomique, Infectiologie et Santé Publique, Université François-Rabelais, Nouzilly, France
| | - Mickaël Riou
- UE-1277, Institut National de la Recherche Agronomique, Plate-Forme d'Infectiologie Expérimentale, Nouzilly, France
| | - Alexandra Blanchard
- UMR 1282, Institut National de la Recherche Agronomique, Infectiologie et Santé Publique, Université François-Rabelais, Nouzilly, France.,Pancosma SA, Geneva, Switzerland
| | - Núria Mach
- UMR 1313, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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Molena RA, Peachey LE, Di Cesare A, Traversa D, Cantacessi C. Cyathostomine egg reappearance period following ivermectin treatment in a cohort of UK Thoroughbreds. Parasit Vectors 2018; 11:61. [PMID: 29370872 PMCID: PMC5785887 DOI: 10.1186/s13071-018-2638-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/10/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In spite of the emergence of populations of drug-resistant cyathostomines worldwide, little is known of parasite species responsible for 'early egg shedding' in cohorts of horses subjected to treatment with widely used anthelmintics, e.g. ivermectin (IVM). In this study, we determined the cyathostomine egg reappearance period (ERP) after IVM treatment in a cohort of yearlings from a large Thoroughbred (TB) stud farm in the United Kingdom, and identified species of cyathostomines with reduced ERP using a combination of fundamental parasitology techniques coupled with advanced molecular tools. METHODS Individual faecal samples were collected from TB yearlings with cyathostomine infection prior to IVM treatment, as well as at 14, 21, 28, 35, 42 and 49 days post-treatment. Faecal egg counts (FEC) were performed for each individual sample for determination of ERPs. In addition, individual larval cultures were performed and representative numbers of third-stage larvae (L3s) harvested from each culture were subjected to molecular species identification via PCR-Reverse Line Blot (RLB). RESULTS Prior to IVM treatment, 11 cyathostomine species were detected in faecal samples from TB horses enrolled in this study, i.e. Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicocyclus nassatus, Cylicostephanus calicatus, Cyathostomum pateratum, Cylicocyclus radiatus, Paraposteriostomum mettami, Coronocyclus labratus, Cylicocyclus insigne and Cylicocyclus radiatus variant A. Of these, eggs of Cya. catinatum, Cys. longibursatus, Cyc. nassatus and Cyc. radiatus could be detected at 28 days post-treatment, while from day 42 onwards, cyathostomine species composition reflected data obtained pre-IVM treatment, with the exception of eggs of Cor. labratus and Cyc. insigne which could no longer be detected post-IVM administration. CONCLUSIONS This study provides valuable data on the occurrence of IVM-resistance in cyathostomines in the UK. Nevertheless, further investigations are needed to shed light on the prevalence and incidence of drug-resistance in this country, as well as other areas of the world where equine trade is substantial.
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Affiliation(s)
- Rebecca A Molena
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Laura E Peachey
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Angela Di Cesare
- Faculty of Veterinary Medicine, University of Teramo, Località Piano d'Accio, Teramo, Italy
| | - Donato Traversa
- Faculty of Veterinary Medicine, University of Teramo, Località Piano d'Accio, Teramo, Italy
| | - Cinzia Cantacessi
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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Rose Vineer H, Vande Velde F, Bull K, Claerebout E, Morgan E. Attitudes towards worm egg counts and targeted selective treatment against equine cyathostomins. Prev Vet Med 2017; 144:66-74. [DOI: 10.1016/j.prevetmed.2017.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 04/30/2017] [Accepted: 05/01/2017] [Indexed: 10/19/2022]
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Tzelos T, Matthews J. Anthelmintic resistance in equine helminths and mitigating its effects. IN PRACTICE 2016. [DOI: 10.1136/inp.i5287] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Rosanowski SM, Scott I, Sells PD, Rogers CW, Bolwell CF. Cross-sectional survey of parasite control practices on Thoroughbred and Standardbred training yards in New Zealand. Equine Vet J 2016; 48:387-93. [DOI: 10.1111/evj.12558] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/13/2015] [Indexed: 11/28/2022]
Affiliation(s)
- S. M. Rosanowski
- Veterinary Epidemiology; Economics and Public Health Group; Royal Veterinary College; Hatfield Hertfordshire UK
| | - I. Scott
- Institute of Veterinary Animal and Biomedical Sciences; Massey University; Palmerston North New Zealand
| | - P. D. Sells
- Kaipaki Veterinary Services; Windsor Park Stud; Cambridge New Zealand
| | - C. W. Rogers
- Equine Research Centre; Institute of Veterinary Animal and Biomedical Sciences; Massey University; Palmerston North New Zealand
| | - C. F. Bolwell
- Equine Research Centre; Institute of Veterinary Animal and Biomedical Sciences; Massey University; Palmerston North New Zealand
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13
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Matthews J, Lester H. Control of equine nematodes: making the most of faecal egg counts. IN PRACTICE 2015. [DOI: 10.1136/inp.h6139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sallé G, Cabaret J. A survey on parasite management by equine veterinarians highlights the need for a regulation change. Vet Rec Open 2015; 2:e000104. [PMID: 26421153 PMCID: PMC4581345 DOI: 10.1136/vetreco-2014-000104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 05/25/2015] [Accepted: 06/16/2015] [Indexed: 11/06/2022] Open
Abstract
Introduction In-depth knowledge of the use of anthelminthics in the field, especially by veterinarians, is required to design more sustainable parasite control strategies. Materials and methods An online survey was sent by e-mail to 940 equine veterinary practitioners to describe their equine practice, their awareness about parasites and the management strategies they apply. Results Gastrointestinal parasites were generally considered (68%) as an issue of moderate importance. Drug efficacy failure was a minor or moderate issue for 47% and 48% of responders, respectively. Parasite management mostly relied on the use of systematic calendar treatments across a wide variety of horse owners (ie, riding schools, studs or hobby horse owners). Almost half of the practitioners (42%) never performed Faecal Egg Count (FEC) before drenching. Horse owners or their employees in charge of equines were reported to be the only person managing drenching in 59% of the collected answers. This was associated with the report of many off-label uses of anthelmintics and the frequent buying of drugs using the internet. Conclusions Given the critical situation regarding anthelmintic resistance, it seems necessary for veterinarians to reclaim parasite management and prevention as a specific topic. Implementation of stricter regulations for use of anthelmintics, like the one applied in Denmark, may make parasitic management in equids more sustainable.
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Affiliation(s)
- Guillaume Sallé
- INRA, UMR1282 Infectiologie et Santé Publique , Nouzilly , France ; Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique , Tours , France
| | - Jacques Cabaret
- INRA, UMR1282 Infectiologie et Santé Publique , Nouzilly , France ; Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique , Tours , France
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Sallé G, Cortet J, Koch C, Reigner F, Cabaret J. Economic assessment of FEC-based targeted selective drenching in horses. Vet Parasitol 2015; 214:159-66. [PMID: 26414907 DOI: 10.1016/j.vetpar.2015.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 10/23/2022]
Abstract
In the face of an increased prevalence of drug-resistant cyathostomin populations, a targeted selective treatment (TST) strategy based on Faecal Egg Counts (FECs) has been proposed as an alternative management strategy. However, associated costs may be a barrier to the uptake of this strategy. Our study aims to provide an economic assessment of FEC-based TST. FECs were determined in a Welsh pony herd thrice a year from 2010 to 2014. This database was used to explore the impact of FEC price, sampling strategy (individual or pooled) and labour-associated costs. Drug price was set at the cheapest level, hence providing a conservative framework to determine the maximum viable FEC price in the context of a cost-driven horse industry. The maximum viable FEC price for a cost-efficient individual based strategy was determined by an in silico bootstrap approach consisting of randomly sampling 1000 virtual pony herds of various sizes (1 to 100 ponies) from the available database and estimating the associated costs (FEC price ranging from € 1 to € 10, anthelmintic costs and labour-associated costs). The costs and benefits of the pooling strategy that consists of basing the decision to treat on group FEC values were also investigated. This is thought to reduce FEC-based costs but may result in highly infected individuals being left undrenched, i.e. in false-negatives, as a result of FEC overdispersion. For various pool-sizes (1-20 ponies) and various cut-off thresholds (50-200 eggs/g), we sampled 1000 pony herds in silico to estimate the associated costs and determine the number of positive ponies within a negative pool. Following these simulations, pool-based FECs of various sizes were performed on 40 ponies to compare predictions with real data. Within 4 years, anthelmintic costs were cut by 80%, albeit with free FECs. In silico estimations suggested that an individual FEC-based TST would not be cost-efficient in this context for an FEC price above € 5. With a pooled FEC strategy, the proportion of false-negatives never exceeded 15% of the pool size. The combination of a 14-pony pool and a cut-off value of 150 eggs/g minimized total costs while keeping the number of false negatives to a reasonable level. Real data obtained from infected ponies however, suggested that pool size should not exceed 10 individuals, since the inhomogeneous mixing of faeces of larger pools probably reduced the correlation between average pooled FECs and the mean of individual FECs. Our study provides an economic framework that could be valuable for emphasizing the use of FEC-based approaches in the field.
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Affiliation(s)
- Guillaume Sallé
- INRA, UMR1282 Infectiologie et Sante Publique, F-37380 Nouzilly, France; Universite Francois Rabelais, UMR1282 Infectiologie et Sante Publique, F-37000 Tours, France.
| | - Jacques Cortet
- INRA, UMR1282 Infectiologie et Sante Publique, F-37380 Nouzilly, France; Universite Francois Rabelais, UMR1282 Infectiologie et Sante Publique, F-37000 Tours, France
| | - Christine Koch
- INRA, UMR1282 Infectiologie et Sante Publique, F-37380 Nouzilly, France; Universite Francois Rabelais, UMR1282 Infectiologie et Sante Publique, F-37000 Tours, France
| | | | - Jacques Cabaret
- INRA, UMR1282 Infectiologie et Sante Publique, F-37380 Nouzilly, France; Universite Francois Rabelais, UMR1282 Infectiologie et Sante Publique, F-37000 Tours, France
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Scott I, Bishop RM, Pomroy WE. Anthelmintic resistance in equine helminth parasites - a growing issue for horse owners and veterinarians in New Zealand? N Z Vet J 2015; 63:188-98. [PMID: 25608588 DOI: 10.1080/00480169.2014.987840] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
There is growing concern that given the high frequency with which anthelmintics are being administered to many horses, anthelmintic resistance amongst equine helminth populations will be an increasing problem, rendering many of the currently available products unusable with little prospect of new products becoming available, at least in the near future. Worldwide, much reliance has been placed on the macrocyclic lactone (ML) group of anthelmintics, but resistance has been reported to these products as well as to the two other major anthelmintic classes used in this species, the benzimidazoles (BZ) and the tetrahydropyrimidines (e.g. pyrantel). In New Zealand, resistance has been reported to the ML and BZ groups, but not yet to pyrantel. As an alternative to interval-based anthelmintic regimens, the highly overdispersed nature of parasite populations in horses can be utilised to decide whether treatment is required, based on whether or not animals exceed a predetermined level of shedding of parasite eggs. If well managed, such a targeted and selective approach can be utilised to eliminate the majority of egg output whilst still providing a refuge for susceptible parasites to persist. Such a system would require that an adequate standard of monitoring be in place and cognisance needs to be taken of parasites or their lifecycle stages that cannot be diagnosed by routine methods. At the same time, using anthelmintics with high levels of efficacy, avoiding practices such as under-dosing, as well as utilising non-chemical means of parasite control when possible, e.g. regular removal of faeces from pasture, should all be considered. Combinations of anthelmintics, specifically of anthelmintics that target the same or a similar spectrum of parasite species, should play an important role in parasite control in horses. As well as providing arguably the highest levels of efficacy, combinations may also slow the rate at which anthelmintic resistance develops.
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Affiliation(s)
- I Scott
- a Infectious Diseases and Public Health Group , Institute of Veterinary, Animal and Biomedical Sciences, Massey University , Private Bag 11222, Palmerston North , New Zealand
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Robert M, Hu W, Nielsen MK, Stowe CJ. Attitudes towards implementation of surveillance-based parasite control on Kentucky Thoroughbred farms - Current strategies, awareness and willingness-to-pay. Equine Vet J 2014; 47:694-700. [DOI: 10.1111/evj.12344] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 08/13/2014] [Indexed: 11/28/2022]
Affiliation(s)
- M. Robert
- Department of Agricultural Economics; University of Kentucky; Lexington USA
| | - W. Hu
- Department of Agricultural Economics; University of Kentucky; Lexington USA
- College of Economics and Management; Huazhong Agricultural University; China
| | - M. K. Nielsen
- M.H. Gluck Equine Research Center; Department of Veterinary Science; University of Kentucky; Lexington USA
| | - C. J. Stowe
- Department of Agricultural Economics; University of Kentucky; Lexington USA
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Matthews JB. Anthelmintic resistance in equine nematodes. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2014; 4:310-5. [PMID: 25516842 PMCID: PMC4266799 DOI: 10.1016/j.ijpddr.2014.10.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Overuse of anthelmintics in horses has reduced disease, but led to widespread resistance. Benzimidazole, tetrahydropyrimidine and macrocyclic lactone resistance in cyathostomins. Ivermectin resistance common in Parascaris equorum. Good grazing management must be integrated with targeted anthelmintic treatments. Progress in novel diagnostics to define pre-patent worm levels is described.
Anthelmintics have been applied indiscriminately to control horse nematodes for over 40 years. Three broad-spectrum anthelmintic classes are currently registered for nematode control in horses: benzimidazoles (fenbendazole, oxibendazole), tetrahydropyrimidines (pyrantel) and macrocyclic lactones (ivermectin, moxidectin). Generally, control strategies have focused on nematode egg suppression regimens that involve the frequent application of anthelmintics to all horses at intervals based on strongyle egg reappearance periods after treatment. The widespread use of such programmes has substantially reduced clinical disease, especially that associated with large strongyle species; however, high treatment frequency has led to considerable selection pressure for anthelmintic resistance, particularly in cyathostomin species. Field studies published over the last decade indicate that benzimidazole resistance is widespread globally in cyathostomins and there are also many reports of resistance to pyrantel in these worms. Cyathostomin resistance to macrocyclic lactone compounds is emerging, principally measured as a reduction in strongyle egg reappearance time observed after treatment. Ivermectin resistance is a further concern in the small intestinal nematode, Parascaris equorum, an important pathogen of foals. These issues indicate that horse nematodes must now be controlled using methods less dependent on anthelmintic use and more reliant on management practices designed to reduce the force of infection in the environment. Such strategies include improved grazing management integrated with targeted anthelmintic administration involving faecal egg count (FEC)-directed treatments. The latter require that the supporting diagnostic tests available are robust and practically applicable. Recent research has focused on maximising the value of FEC analysis in horses and on optimizing protocols for anthelmintic efficacy testing. Other studies have sought to develop diagnostics that will help define levels of pre-patent infection. This review describes recent advances in each of these areas of research.
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Affiliation(s)
- Jacqueline B Matthews
- Moredun Research Institute, Pentlands Science Park, Edinburgh, Midlothian, EH26 0PZ, UK
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Anthelmintic efficacy on UK Thoroughbred stud farms. Int J Parasitol 2014; 44:507-14. [PMID: 24746779 DOI: 10.1016/j.ijpara.2014.03.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 11/23/2022]
Abstract
Anthelmintic drugs have been applied indiscriminately to control horse nematodes for over 40 years. We undertook a comprehensive study to investigate efficacy of the four available broad-spectrum anthelmintic drugs on 16 Thoroughbred stud farms using the faecal egg count reduction test. Efficacy against strongyles was determined by calculating the percentage of reduction in faecal egg count between the group mean at Day 0 and Days 14-17 post-treatment and the 95% lower confidence intervals estimated by non-parametric bootstrapping. Individual strongyle faecal egg count reduction tests (n=429) were performed in which 179, 131, 89 and 30 horses were administered ivermectin, moxidectin, pyrantel and fenbendazole, respectively. Moxidectin was efficacious in all tests (faecal egg count reduction range: 99.8-100%; 95% lower confidence intervals range: 96.8-100%) and reduced efficacy of ivermectin (faecal egg count reduction range: 85.7-100%; 95% lower confidence intervals range: 65-100%) was observed in one group of yearlings. Reduced pyrantel efficacy was observed in five groups of yearlings (faecal egg count reduction range: 0-73%; 95% lower confidence intervals range: 0-59.5%), but pyrantel was found to be efficacious when administered to mares (faecal egg count reduction range: 98-99.4%; 95% lower confidence intervals range: 91.8-99.3%). Low efficacy of fenbendazole was always observed (faecal egg count reduction range: 0.4-41%; 95% lower confidence intervals not calculable). Two further methods for estimating efficacy were applied and outputs obtained using all methodologies were in agreement. Efficacy against Parascaris equorum was assessed on four farms: fenbendazole had acceptable efficacy (faecal egg count reduction range: 97.5-99.9%; 95% lower confidence intervals range: 96.3-99.1%), but reduced efficacy of ivermectin was observed (faecal egg count reduction range: 25.5-91.2%; 95% lower confidence intervals range: 6.7-82.4%). Strongyle faecal egg count were analysed at approximately 2 week intervals for up to 12 weeks after anthelmintic drug administration to determine the egg reappearance period for moxidectin, ivermectin and pyrantel. The egg reappearance period for all three anthelmintic drugs was shorter than previously observed. Overall, our results indicate that ivermectin and moxidectin administration provided acceptable efficacy at 14 days; however, egg reappearance period results suggest that these products are working less effectively than measured previously. As shortened egg reappearance period is believed to be an early indicator of resistance, this highlights the issue of impending multi-drug resistance in strongyles on stud farms.
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Affiliation(s)
- J. B. Matthews
- Disease Control; Moredun Research Institute; Edinburgh UK
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Lester HE, Matthews JB. Faecal worm egg count analysis for targeting anthelmintic treatment in horses: Points to consider. Equine Vet J 2013; 46:139-45. [DOI: 10.1111/evj.12199] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 10/05/2013] [Indexed: 11/28/2022]
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