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Alm YH, Osterman-Lind E, Martin F, Lindfors R, Roepstorff N, Hedenström U, Fredriksson I, Halvarsson P, Tydén E. Retained efficacy of ivermectin against cyathostomins in Swedish horse establishments practicing selective anthelmintic treatment. Vet Parasitol 2023; 322:110007. [PMID: 37639919 DOI: 10.1016/j.vetpar.2023.110007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/31/2023]
Abstract
Cyathostominae are ubiquitous to grazing horses and regarded the most prevalent internal parasite in the horse. Unfortunately, decades of indiscriminate use of anthelmintic drugs have resulted in the development of resistance in cyathostomins to all currently available drug groups, the most recent being a documented lack of efficacy to the macrocyclic lactones (ML). In vivo determination of anthelmintic resistance in horses most often utilises the faecal egg count reduction test (FECRT). Further, a shortened egg reappearance period (ERP) can indicate a change in response to the applied treatment and suggest an upcoming reduction of efficacy. Although both true resistance as demonstrated by the FECRT and shorter ERPs after ML treatment have now been shown in cyathostomins worldwide, the efficacy of ML as regards to cyathostomins in Sweden is currently unknown. The aim of the present study was therefore to determine FECRTs and ERPs after ivermectin (IVM) treatment in Swedish horses. Sixteen equestrian establishments with a minimum of six horses excreting at least 150 eggs per gram faeces (EPG) at screening were selected. For each establishment, FECRTs and ERPs were determined by collecting faecal samples prior to and 14 days after IVM treatment (200 µg/kg), and thereafter at weekly intervals for a total of eight weeks. All participants responded to a questionnaire detailing pasture management methods and anthelmintic routines.Questionnaire results showed that the majority of establishments (69%) only treated horses with anthelmintic drugs if indicated by faecal diagnostics and all of the establishments had a mean FECRT exceeding 99.0% and ERPs ranging from six to over eight weeks. The ERP was shown to increase with age as young individuals were shown to excrete cyathostomin eggs earlier after treatment compared with older horses (R = 0.21, p = 0.015). Riding schools, stud farms and those declaring not to use separate summer and winter paddocks had significantly shorter ERPs (p <0.01).In conclusion, retained ERPs and no confirmed resistance to IVM were found in Swedish equine establishments practising selective anthelmintic treatment, and supports the use of selective deworming regimens as a means of reducing the risk of anthelmintic resistance development.
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Affiliation(s)
- Ylva Hedberg Alm
- Department of Biomedical Science and Veterinary Public Health, Parasitology Unit, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
| | - Eva Osterman-Lind
- Department of Microbiology, Section for Parasitology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
| | - Frida Martin
- Department of Biomedical Science and Veterinary Public Health, Parasitology Unit, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Rebecca Lindfors
- Ambulatory Clinic, University Animal Hospital, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Nina Roepstorff
- Ridskolan Strömsholm AB, Stallbacken 6, Knytpunkten, SE-734 94 Strömsholm, Sweden
| | | | | | - Peter Halvarsson
- Department of Biomedical Science and Veterinary Public Health, Parasitology Unit, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Eva Tydén
- Department of Biomedical Science and Veterinary Public Health, Parasitology Unit, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
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2
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Macdonald SL, Abbas G, Ghafar A, Gauci CG, Bauquier J, El-Hage C, Tennent-Brown B, Wilkes EJA, Beasley A, Jacobson C, Cudmore L, Carrigan P, Hurley J, Beveridge I, Hughes KJ, Nielsen MK, Jabbar A. Egg reappearance periods of anthelmintics against equine cyathostomins: The state of play revisited. Int J Parasitol Drugs Drug Resist 2022; 21:28-39. [PMID: 36543048 PMCID: PMC10105024 DOI: 10.1016/j.ijpddr.2022.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/11/2022] [Accepted: 12/11/2022] [Indexed: 12/14/2022]
Abstract
Cyathostomins are the most common and highly prevalent parasites of horses worldwide. Historically, the control of cyathostomins has mainly relied on the routine use of anthelmintic products. Increasing reports on anthelmintic resistance (AR) in cyathostomins are concerning. A potential method proposed for detecting emerging AR in cyathostomins has been estimating the egg reappearance period (ERP). This paper reviews the data available for the ERP of cyathostomins against the three major classes of anthelmintics, macrocyclic lactones, tetrahydropyrimidines, and benzimidazoles. Published peer-reviewed original research articles were obtained from three databases (PubMed, CAB Direct and Web of Science) and were evaluated for their inclusion in a systematic review. Subsets of articles were then subjected to a review of ERP data. A total of 54 (of 134) studies published between 1972 and 2022 met the criteria for inclusion in the systematic review. Until the beginning of 2022, there was no agreed definition of the ERP; eight definitions of ERP were identified in the literature, complicating the comparison between studies. Additionally, potential risk factors for the shortening of the ERP, including previous anthelmintic use and climate, were frequently not described. Reports of shortened ERP for moxidectin and ivermectin are frequent: 20 studies that used comparable ERP definitions reported shortened moxidectin and ivermectin ERPs of 35 and 28 days, respectively. It is unclear whether the ERPs of these anthelmintics reduced to such levels are due to the development of AR or some biological factors related to horses, cyathostomin species, and/or the environment. The ERPs for other anthelmintics, such as fenbendazole and pyrantel, were frequently not reported due to established resistance against these drugs. Future research in horses is required to understand the mechanism(s) behind the shortening of ERP for cyathostomins. Based on this systematic review, we propose recommendations for future ERP studies.
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Affiliation(s)
- Stephanie L Macdonald
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Ghazanfar Abbas
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Abdul Ghafar
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Charles G Gauci
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Jenni Bauquier
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Charles El-Hage
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Brett Tennent-Brown
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | | | - Anne Beasley
- School of Agriculture and Food Sciences, University of Queensland, Gatton, Queensland, Australia
| | - Caroline Jacobson
- Centre for Animal Production and Health, Murdoch University, Murdoch, Western Australia, Australia
| | - Lucy Cudmore
- Scone Equine Hospital, Scone, New South Wales, Australia
| | - Peter Carrigan
- Scone Equine Hospital, Scone, New South Wales, Australia
| | - John Hurley
- Swettenham Stud, Nagambie, Victoria, Australia
| | - Ian Beveridge
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Kristopher J Hughes
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Martin K Nielsen
- M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Abdul Jabbar
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia.
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3
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Anthelmintic resistance in equine nematodes: Current status and emerging trends. Int J Parasitol Drugs Drug Resist 2022; 20:76-88. [PMID: 36342004 PMCID: PMC9630620 DOI: 10.1016/j.ijpddr.2022.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022]
Abstract
Anthelmintic resistance is reported in equine nematodes with increasing frequency in recent years, and no new anthelmintic classes have been introduced during the past 40 years. This manuscript reviews published literature describing anthelmintic resistance in cyathostomins, Parascaris spp., and Oxyuris equi with special emphasis on larvicidal efficacy against encysted cyathostomin larvae and strongylid egg reappearance periods (ERP). Resistance to benzimidazoles and pyrimidines is highly prevalent in cyathostomin populations around the world, and macrocyclic lactone resistance has been documented in cyathostomins in recent years as well. Two recent studies have documented resistance to the larvicidal regimen of fenbendazole, whereas the larvicidal efficacy of moxidectin is variable, but with no evidence of a reduction from historic levels. In the 1990s, ERP estimates were 8-10 and 12-16 weeks for ivermectin and moxidectin, respectively, while several studies published after year 2000 found ERPs to be 5 weeks for both compounds. This is a clear change in anthelmintic performance, but it remains unclear if this is due to development of anthelmintic resistance or selection for other biological traits leading to a quicker resumption of strongylid egg shedding following anthelmintic treatment. Macrocyclic lactone resistance is common in Parascaris spp. around the world, but recent reports suggests that resistance to the two other classes should be monitored as well. Finally, O. equi has been reported resistant to ivermectin and moxidectin in countries representing four continents. In conclusion, multi-drug resistance is becoming the norm in managed cyathostomin populations around the world, and a similar pattern may be emerging in Parascaris spp. More work is required to understand the mechanisms behind the shortened ERPs, and researchers and veterinarians around the world are encouraged to routinely monitor anthelmintic efficacy against equine nematodes.
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Jürgenschellert L, Krücken J, Bousquet E, Bartz J, Heyer N, Nielsen MK, von Samson-Himmelstjerna G. Occurrence of Strongylid Nematode Parasites on Horse Farms in Berlin and Brandenburg, Germany, With High Seroprevalence of Strongylus vulgaris Infection. Front Vet Sci 2022; 9:892920. [PMID: 35754549 PMCID: PMC9226773 DOI: 10.3389/fvets.2022.892920] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/22/2022] [Indexed: 11/26/2022] Open
Abstract
The infection of horses with strongylid nematodes is highly prevalent, with multi-species infections being the rule. Strongylus spp. and in particular Strongylus vulgaris are amongst the most pathogenic strongyle equine parasites. Presumably due to regular strategic anthelmintic treatments in combination with long prepatencies, prevalence of these worms was severely reduced in past decades. In this study, 484 horses from 48 farms in Berlin/Brandenburg, Germany were sampled between May 2017 and January 2018. Mini-FLOTAC and combined sedimentation/flotation were used to analyse faecal samples and larval cultures were carried out from individual strongyle infected horses for molecular testing for Strongylus spp. infection. Additionally, for Strongylus vulgaris, antibodies against a recombinant larval antigen were quantified in an ELISA. Strongyle type eggs were detected in 66.7% of the individual faecal samples. Nematode DNA was amplifiable from 311 samples and S. vulgaris and Strongylus edentatus were detected in four (1.3%) and 10 (6.3%) of these, respectively, the latter using a novel high-resolution-melt PCR targeting S. edentatus, Strongylus equinus, and Strongylus asini. On the farm level, prevalence for Strongylus spp. by PCR was 12.5%. Applying a conservative cut-off (sensitivity 0.43, specificity 0.96), 21.2% of all serum samples were positive for antibodies against S. vulgaris larvae (83.3% prevalence on farm level). Newly developed pyrosequencing assays to analyse putatively benzimidazole resistance associated polymorphisms in codons 167, 198, and 200 of the isotype 1 β-tubulin gene of S. vulgaris did not detect such polymorphisms in the four positive samples. Low age and increasing access to pasture were risk factors for egg shedding and seropositivity for S. vulgaris. Time since last treatment increased whereas use of moxidectin and ivermectin for the last treatment decreased the risk for strongyle egg shedding. Noteworthy, horses under selective treatment had significantly higher odds to be seropositive for anti-S. vulgaris antibodies than horses treated four times per year (odds ratio 4.4). The serological findings suggest that exposure to S. vulgaris is considerably higher than expected from direct diagnostic approaches. One potential explanation is the contamination of the environment by a few infected horses, leading to the infection of many horses with larvae that never reach maturity due to regular anthelmintic treatments.
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Affiliation(s)
- Laura Jürgenschellert
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | | | - Jürgen Bartz
- Virbac Tierazneimittel GmbH, Bad Oldesloe, Germany
| | - Nina Heyer
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Martin K. Nielsen
- M.H. Gluck Equine Research Center, University of Kentucky, Lexington, KY, United States
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5
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A Survey of Control Strategies for Equine Small Strongyles in Lithuania. Helminthologia 2021; 58:225-232. [PMID: 34934386 PMCID: PMC8647954 DOI: 10.2478/helm-2021-0031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/29/2021] [Indexed: 11/24/2022] Open
Abstract
Anthelmintic resistance (AR) in equine cyathostomins is being reported all over the world. In Lithuania, however, the last study on this subject was published more than fifteen years ago, thus little is known about the current situation. The aim of this study was to determine the factors that may associated with the development of AR on equine studs in Lithuania. A questionnaire containing seven open-ended and nine closed multiple-choice questions about worm control strategies, use of anthelmintic substances and stable management practices was posted to 71 randomly selected horse establishments in Lithuania. Replies were obtained from a total of 59 stables, representing 83 % of officially established stud farms in Lithuania. The results showed that more than 80 % of these establishments performed pasture management practices such as excrement removal from stables and pasture, 56 % mowed their pasture, 31 % practised mixed or rotational grazing with other species, and 97 % of the horses were routinely dewormed. Macrocyclic lactones (ML) (58 %, n=33) were the most commonly used drugs, followed by benzimidazoles (BZ) (24 %, n=14) and tetrahydropyrimidines (THP) (19 %, n=10). The majority of farms (60 %) treated horses four times per year and 68 % estimated the weight of the horses by eye before treatment. About 36 % of respondents had heard of faecal egg counts (FEC), but only 17 % used the test and as few as 9 % had tested their herds for AR with faecal egg count reduction tests (FECRT). The results demonstrate that there is scope for improving routines for worm control in many horse establishments in Lithuania. In order to increase knowledge and reduce the risk of the spread of AR, diagnostic methods should be adopted in a collaboration between stud farms and veterinary practitioners.
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Ahuir-Baraja AE, Cibot F, Llobat L, Garijo MM. Anthelmintic resistance: is a solution possible? Exp Parasitol 2021; 230:108169. [PMID: 34627787 DOI: 10.1016/j.exppara.2021.108169] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 09/28/2021] [Accepted: 10/05/2021] [Indexed: 01/05/2023]
Abstract
More than 50 years after anthelmintic resistance was first identified, its prevalence and impact on the animal production industry continues to increase across the world. The term "anthelmintic resistance" (AR) can be briefly defined as the reduction in efficacy of a certain dose of anthelmintic drugs (AH) in eliminating the presence of a parasite population that was previously susceptible. The main aim of this study is to examine anthelmintic resistance in domestic herbivores. There are numerous factors playing a role in the development of AR, but the most important is livestock management. The price of AH and the need to treat a high number of animals mean that farmers face significant costs in this regard, yet, since 1981, little progress has been made in the discovery of new molecules and the time and cost required to bring a new AH to market has increased dramatically in recent decades. Furthermore, resistance has also emerged for new AH, such as monepantel or derquantel. Consequently, ruminant parasitism cannot be controlled solely by using synthetic chemicals. A change in approach is needed, using a range of preventive measures in order to achieve a sustainable control programme. The use of nematophagous fungi or of plant extracts rich in compounds with anthelmintic properties, such as terpenes, condensed tannins, or flavonoids, represent potential alternatives. Nevertheless, although new approaches are showing promising results, there is still much to do. More research focused on the control of AR is needed.
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Affiliation(s)
- A E Ahuir-Baraja
- Parasitology and Parasitic Diseases Research Group (PARAVET), Department of Animal Production and Health, Veterinary Public Health and Food Science and Technology (PASAPTA), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, Spain
| | - F Cibot
- Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, Spain
| | - L Llobat
- Microbiological Agents Associated with Animal Reproduction Research Group (PROVAGINBIO), Department of Animal Production and Health, Veterinary Public Health and Food Science and Technology (PASAPTA), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, Spain.
| | - M M Garijo
- Parasitology and Parasitic Diseases Research Group (PARAVET), Department of Animal Production and Health, Veterinary Public Health and Food Science and Technology (PASAPTA), Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, Spain
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7
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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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8
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Mayinda GDK, Serreau D, Gesbert A, Reigner F, Sutra JF, Lespine A, Sallé G. Ivermectin treatment in lactating mares results in suboptimal ivermectin exposure in their suckling foals. Vet Parasitol 2021; 296:109511. [PMID: 34237517 DOI: 10.1016/j.vetpar.2021.109511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 06/23/2021] [Accepted: 06/26/2021] [Indexed: 10/20/2022]
Abstract
The management of equine strongyles has become problematic over the last decade because of an increased prevalence of drug-resistant isolates worldwide. Therapeutic options are therefore limited, leaving macrocyclic lactones as the most often effective drug class. However, their lipophilic properties result in a long-lasting elimination that could favour drug resistance selection. As a result, ivermectin treatment in lactating mares could promote suboptimal exposure of their foal parasites to ivermectin, thereby selecting for more resistant worms. To test for this putative transfer, we selected two groups of six foal-mare pairs, one group of mares receiving ivermectin and the other being left untreated. We compared faecal egg count trajectories in foals from the two groups and quantified plasma ivermectin concentrations in ivermectin treated mares and their foals during seven days. Our results showed limited but sustained plasmatic exposure of foals associated with non-significant faecal egg count reduction (P = 0.69). This suggests that ivermectin treatment in lactating mares results in suboptimal exposure to the drug in their foal.
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Affiliation(s)
| | - Delphine Serreau
- NRAE, Université de Tours, UMR1282 Infectiologie et Santé Publique, F-37380, Nouzilly, France
| | - Amandine Gesbert
- INRAE, UE1297 Physiologie Animale de l'Orfrasière, F-37380, Nouzilly, France
| | - Fabrice Reigner
- INRAE, UE1297 Physiologie Animale de l'Orfrasière, F-37380, Nouzilly, France
| | - Jean-François Sutra
- INRAE, Ecole Nationale Vétérinaire de Toulouse, UMR1436 INTHERES, F-31076, Toulouse, France
| | - Anne Lespine
- INRAE, Ecole Nationale Vétérinaire de Toulouse, UMR1436 INTHERES, F-31076, Toulouse, France
| | - Guillaume Sallé
- NRAE, Université de Tours, UMR1282 Infectiologie et Santé Publique, F-37380, Nouzilly, France.
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9
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Hedberg-Alm Y, Penell J, Riihimäki M, Osterman-Lind E, Nielsen MK, Tydén E. Parasite Occurrence and Parasite Management in Swedish Horses Presenting with Gastrointestinal Disease-A Case-Control Study. Animals (Basel) 2020; 10:E638. [PMID: 32272754 PMCID: PMC7222828 DOI: 10.3390/ani10040638] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/29/2020] [Accepted: 03/31/2020] [Indexed: 11/17/2022] Open
Abstract
All grazing horses are exposed to intestinal parasites, which have the potential to cause gastrointestinal disease. In Sweden, there is a concern about an increase in parasite-related equine gastrointestinal disease, in particular Strongylus vulgaris, since the implementation of prescription-only anthelmintics approximately 10 years ago. In a prospective case-control study, parasitological status, using fecal analyses for strongyle egg counts, the presence of Anoplocephala perfoliata eggs and S. vulgaris Polymerase chain reaction (PCR) as well as serology for S. vulgaris, were compared between horses presenting with or without gastrointestinal disease at a University hospital during a one-year period. Information regarding anthelmintic routines and pasture management was gathered with an owner-filled questionnaire. Although the prevalence of S. vulgaris PCR was 5.5%, 62% of horses were positive in the enzyme-linked immunosorbent assay (ELISA) test and horses with peritonitis showed higher antibody levels for S. vulgaris, as compared to other diagnoses or controls. Overall, 36% of the horse owners used only fecal egg counts (FEC), 32% used FEC combined with specific diagnostics for S. vulgaris or A. perfoliata, and 29% dewormed routinely without prior parasite diagnostics. Effective management methods to reduce the parasitic burden on pastures were rare and considering exposure to S. vulgaris appears high; the study indicates a need for education in specific fecal diagnostics and pasture management.
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Affiliation(s)
- Ylva Hedberg-Alm
- Horse Clinic, University Animal Hospital, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Johanna Penell
- Division of Veterinary Nursing, Department of Clinical Sciences, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden;
| | - Miia Riihimäki
- Equine Medicine Unit, Department of Clinical Sciences, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden;
| | - Eva Osterman-Lind
- National Veterinary Institute, Department of Microbiology, Section for Parasitology diagnostics, 751 89 Uppsala, Sweden;
| | - Martin K. Nielsen
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546, USA;
| | - Eva Tydén
- Parasitology Unit, Department of Biomedical Science and Veterinary Public Health, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden;
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10
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Sallé G, Guillot J, Tapprest J, Foucher N, Sevin C, Laugier C. Compilation of 29 years of postmortem examinations identifies major shifts in equine parasite prevalence from 2000 onwards. Int J Parasitol 2020; 50:125-132. [PMID: 31981673 DOI: 10.1016/j.ijpara.2019.11.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/08/2019] [Accepted: 11/14/2019] [Indexed: 11/29/2022]
Abstract
Horses are infected by a wide range of parasite species that form complex communities. Parasite control imposes significant constraints on parasite communities whose monitoring remains, however, difficult to track through time. Postmortem examination is a reliable method to quantify parasite communities. Here, we compiled 1,673 necropsy reports accumulated over 29 years, in the reference necropsy centre from Normandy (France). The burden of non-strongylid species was quantified and the presence of strongylid species was noted. Details of horse deworming history and the cause of death were registered. Building on these data, we investigated the temporal trend in non-strongylid epidemiology and we determined the contribution of parasites to the deaths of horses throughout the study period. Data analyses revealed the seasonal variations of non-strongylid parasite abundance and reduced worm burden in race horses. Beyond these observations, we found a shift in the species responsible for fatal parasitic infection from the year 2000 onward, whereby fatal cyathostominosis and Parascaris spp. infection have replaced cases of death caused by Strongylus vulgaris and tapeworms. A concomitant break in the temporal trend of parasite species prevalence was also found within a 10 year window (1998-2007) that has seen the rise of Parascaris spp. and the decline of both Gasterophilus spp. and tapeworms. A few cases of parasite persistence following deworming were identified, which all occurred after 2000. Altogether, these findings provide insights into major shifts in non-strongylid parasite prevalence and abundance over the last 29 years. They also underscore the critical importance of Parascaris spp. in young equids.
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Affiliation(s)
- G Sallé
- INRAE, U. de Tours, UMR1282 ISP, F-37380, Nouzilly, France.
| | - J Guillot
- Parasitology Department, EA Dynamyc, EnvA, UPEC, USC ANSES, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - J Tapprest
- ANSES Laboratory of Animal Health in Normandy, Goustranville, France
| | - N Foucher
- ANSES Laboratory of Animal Health in Normandy, Goustranville, France
| | - C Sevin
- ANSES Laboratory of Animal Health in Normandy, Goustranville, France
| | - C Laugier
- ANSES Laboratory of Animal Health in Normandy, Goustranville, France
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11
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Cain JL, Foulk D, Jedrzejewski E, Stofanak H, Nielsen MK. The importance of anthelmintic efficacy monitoring: results of an outreach effort. Parasitol Res 2019; 118:2877-2883. [PMID: 31422463 DOI: 10.1007/s00436-019-06423-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 08/07/2019] [Indexed: 11/29/2022]
Abstract
Anthelmintic resistance in equine cyathostomin parasites is widespread. A surveillance-based parasite control program using fecal egg counts (FECs) and fecal egg count reduction tests (FECRTs) to decrease anthelmintic use and monitor treatment efficacy is recommended. The purpose of this study was to examine shifts in equine parasite control program management practices via a short course presented by the Penn State Extension, and to highlight how data collected from these programs is useful for monitoring anthelmintic efficacy on a large scale. Horse owners were enrolled after participating in a short course and filled out questionnaire surveys about their parasite management programs pre and post study, horse information, and farm information. FECs were performed at three time points, and horses above a 300 strongyle eggs per gram cut-off were treated with pyrantel pamoate, fenbendazole, or ivermectin. Two weeks post-treatment, FECRTs were performed to determine treatment efficacy, which included 29 farms with 513 individual treatments. Prior to the study, only 30.6% of farms used FECs, but after the study, 97.3% of farms said they would use FECs in the future. Horses were given an average of 4.1 anthelmintic treatments per year before the study, and post study 89.2% of farms were able to reduce the number of anthelmintic treatments used. Fenbendazole was effective on zero farms, pyrantel pamoate on 7.4% of farms, and ivermectin on 92.9% of farms. This outreach project helped generate information about anthelmintic efficacy levels, causing a shift in practices on participating farms, and collected useful anthelmintic resistance data.
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Affiliation(s)
- Jennifer L Cain
- M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA.
| | - Donna Foulk
- Penn State Extension, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Edward Jedrzejewski
- Department of Animal Science, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Heather Stofanak
- Penn State Extension, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Martin K Nielsen
- M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
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