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Abbas G, Ghafar A, McConnell E, Beasley A, Bauquier J, Wilkes EJA, El-Hage C, Carrigan P, Cudmore L, Hurley J, Gauci CG, Beveridge I, Ling E, Jacobson C, Stevenson MA, Nielsen MK, Hughes KJ, Jabbar A. A national survey of anthelmintic resistance in ascarid and strongylid nematodes in Australian Thoroughbred horses. Int J Parasitol Drugs Drug Resist 2024; 24:100517. [PMID: 38064906 PMCID: PMC10757041 DOI: 10.1016/j.ijpddr.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 11/19/2023] [Accepted: 11/19/2023] [Indexed: 01/02/2024]
Abstract
This study quantified the extent of anthelmintic resistance (AR) in ascarid and strongylid nematodes against commonly used anthelmintics in Australian Thoroughbred horses. Faecal egg count reduction tests (FECRTs, n = 86) and egg reappearance period (ERP) tests were conducted on 22 farms across Australia. Faecal egg counts (FECs) were determined using the modified McMaster technique, and percent faecal egg count reduction (%FECR) was calculated using the Bayesian hierarchical model and hybrid Frequentist/Bayesian analysis method. The results were interpreted using old (published in 1992) and new (2023) research guidelines of the World Association for the Advancement of Veterinary Parasitology (WAAVP). The species composition of strongylid nematodes was detected utilising a DNA-metabarcoding method using pre- and post-treatment samples. Resistance was observed in strongylid nematodes to commonly used single-active and combination anthelmintics, including ivermectin (IVM %FECR range: 82%-92%; 95% lower credible interval (LCI) range: 80%-90%), abamectin (ABM: 73%-92%; 65%-88%), moxidectin (MOX: 89%-91%; 84%-89%), oxfendazole (OFZ: 0%-56%; 0%-31%) and its combination with pyrantel (OFZ + PYR: 0%-82%; 0%-78%). Resistance in Parascaris spp. was observed to IVM (10%-43%; 0%-36%), ABM (0%; 0%) and MOX (0%; 0%). When the new thresholds recommended by the WAAVP were used, AR was detected in six additional FECRTs for strongylids and three more tests for Parascaris spp., introducing resistance to OFZ and OFZ + PYR in the latter. Shortened ERPs (4-6 weeks) of strongylids were observed in 31 FECRTs in which AR was not detected at 2 weeks post-treatment for all the anthelmintics tested. Among cyathostomins, Cylicocyclus nassatus, Cylicostephanus longibursatus and Coronocyclus coronatus were the most prevalent species at 2 weeks post-treatment, whereas the main species appearing at five weeks following treatments with macrocyclic lactones were Cylicocyclus nassatus, Cylicostephanus longibursatus and Cylicocyclus ashworthi. After treatment with OFZ + PYR, the latter three, plus Coronocyclus coronatus and Cyathostomum catinatum, were detected at 5 weeks post-treatment. Overall, the study highlights the prevalence of AR in both ascarids and strongylid nematodes against commonly used anthelmintic products to control worms in Australian horses. The results indicate that ML combination products provided acceptable efficacy at 2 weeks. However, ERP calculations suggest that products work less effectively than previously measured. It is suggested to regularly monitor the efficacy of the anthelmintics and consider changing the worm control practices to better manage worms and AR in Australian horses.
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Affiliation(s)
- Ghazanfar Abbas
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | - Abdul Ghafar
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | - Emma McConnell
- Centre for Animal Production and Health, Murdoch University, Murdoch, Western Australia, Australia
| | - Anne Beasley
- School of Agriculture and Food Sustainability, University of Queensland, Gatton, Queensland 4343, Australia
| | - Jenni Bauquier
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | | | - Charles El-Hage
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | - Peter Carrigan
- Scone Equine Hospital, Scone, New South Wales 2337, Australia
| | - Lucy Cudmore
- Scone Equine Hospital, Scone, New South Wales 2337, Australia
| | - John Hurley
- Swettenham Stud, Nagambie, Victoria 3608, Australia
| | - Charles G Gauci
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | - Ian Beveridge
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | - Elysia Ling
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | - Caroline Jacobson
- Centre for Animal Production and Health, Murdoch University, Murdoch, Western Australia, Australia
| | - Mark A Stevenson
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia
| | - Martin K Nielsen
- M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Kristopher J Hughes
- School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2650, Australia
| | - Abdul Jabbar
- Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria 3030, Australia.
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Ashrafzadeh-Shiraz M, Tavassoli M, Dalir-Naghadeh B, Sazmand A. Impaired efficacy of fenbendazole and ivermectin against intestinal nematodes in adult horses in Iran. Res Vet Sci 2024; 166:105078. [PMID: 37952299 DOI: 10.1016/j.rvsc.2023.105078] [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: 03/25/2023] [Revised: 10/19/2023] [Accepted: 11/02/2023] [Indexed: 11/14/2023]
Abstract
This study aimed to evaluate the efficacy of fenbendazole and ivermectin on strongyles and Parascaris sp. infecting adult riding horses in three regions with different climates. During 2021 and 2022 fecal specimens were randomly collected from 483 horses older than three years in 31 equestrian clubs in Hamedan (n = 217), Yazd (n = 146) and Tabriz cities (n = 120). Eggs were counted by McMaster technique, and the strongyle larvae were identified using coproculture, PCR and sequencing. Horses with strongyles and Parascaris egg counts ≥150 were enrolled in fecal egg count reduction (FECR) examination following treatment with ivermectin or fenbendazole. In total, 26.5% of examined horses were positive with at least one parasite. Infection rates varied in three cities i.e., 25.8% in Hamedan, 28.8% in Yazd, 25% in Tabriz. Fifty-seven horses had FECR measured. FECR below <90% was observed for IVM-strongyle in two horses in Tabriz, for FBZ-strongyle in two horses in Tabriz and two horses in Hamedan, for IVM-Parascaris in one horse in all three cities, and for FBZ-Parascaris in one horse in Yazd. Furthermore, FECR 90-100% was observed in IVM-Parascaris and FBZ -Parascaris groups in Tabriz. Data herein presented demonstrate different degrees of resistance of strongyles and Parascaris infecting horses in Iran against both ivermectin and fenbendazole. Since non-principled use of anthelminthics is common among horse owners, urgency of test-and-treatment strategy should be educated and implemented by policy-making organizations. Evaluating efficacy of different anthelminthics and choosing the most effective treatment in each region is suggested.
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Affiliation(s)
| | - Mousa Tavassoli
- Department of Pathobiology, Faculty of Veterinary Medicine, Urmia University, 5756151818 Urmia, Iran.
| | - Bahram Dalir-Naghadeh
- Department of Internal Disease and Clinical Pathology, Faculty of Veterinary Medicine, Urmia University, 5756151818 Urmia, Iran.
| | - Alireza Sazmand
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, 6517658978 Hamedan, Iran.
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Buono F, Veneziano V, Veronesi F, Molento MB. Horse and donkey parasitology: differences and analogies for a correct diagnostic and management of major helminth infections. Parasitology 2023; 150:1119-1138. [PMID: 37221816 PMCID: PMC10801385 DOI: 10.1017/s0031182023000525] [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: 01/22/2023] [Revised: 04/17/2023] [Accepted: 05/10/2023] [Indexed: 05/25/2023]
Abstract
In June 2022, at the XXXII Conference of the Italian Society of Parasitology, the parallels of the main endoparasitic infections of horses and donkeys were discussed. Although these 2 species are genetically different, they can be challenged by a similar range of parasites (i.e. small and large strongyles, and Parascaris spp.). Although equids can demonstrate some level of resilience to parasites, they have quite distinct helminth biodiversity, distribution and intensity among different geographical locations and breeds. Heavily infected donkeys may show fewer clinical signs than horses. Although parasite control is primarily provided to horses, we consider that there may be a risk of drug-resistance parasitic infection through passive infection in donkeys when sharing the same pasture areas. Knowing the possible lack of drug efficacy (<90 or 80%), it is advocated the use of selective treatment for both species based on fecal egg counts. Adult horses should receive treatment when the threshold exceeds 200–500 eggs per gram (EPG) of small strongyles. Moreover, considering that there are no precise indications in donkeys, a value >300 EPG may be a safe recommendation. We have highlighted the main points of the discussion including the dynamics of helminth infections between the 2 species.
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Affiliation(s)
- Francesco Buono
- Department of Veterinary Medicine and Animal Productions, University of Naples 'Federico II', Naples, Italy
| | - Vincenzo Veneziano
- Department of Veterinary Medicine and Animal Productions, University of Naples 'Federico II', Naples, Italy
| | - Fabrizia Veronesi
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | - Marcelo Beltrão Molento
- Laboratory of Veterinary Clinical Parasitology, Department of Veterinary Medicine, Federal University of Parana, Curitiba, PR, Brazil
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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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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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Boelow H, Krücken J, Thomas E, Mirams G, von Samson-Himmelstjerna G. Comparison of FECPAK G2, a modified Mini-FLOTAC technique and combined sedimentation and flotation for the coproscopic examination of helminth eggs in horses. Parasit Vectors 2022; 15:166. [PMID: 35549990 PMCID: PMC9097362 DOI: 10.1186/s13071-022-05266-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 03/30/2022] [Indexed: 01/24/2023] Open
Abstract
Background Due to high prevalence of anthelmintic resistance in equine helminths, selective treatment is increasingly promoted and in some countries a positive infection diagnosis is mandatory before treatment. Selective treatment is typically recommended when the number of worm eggs per gram faeces (epg) exceeds a particular threshold. In the present study we compared the semi-quantitative sedimentation/flotation method with the quantitative methods Mini-FLOTAC and FECPAKG2 in terms of precision, sensitivity, inter-rater reliability and correlation of worm egg counts to improve the choice of optimal diagnostic tools. Methods Using sedimentation/flotation (counting raw egg numbers up to 200), we investigated 1067 horse faecal samples using a modified Mini-FLOTAC approach (multiplication factor of 5 to calculate epgs from raw egg counts) and FECPAKG2 (multiplication factor of 45). Results Five independent analyses of the same faecal sample with all three methods revealed that variance was highest for the sedimentation/flotation method while there were no significant differences between methods regarding the coefficient of variance. Sedimentation/flotation detected the highest number of samples positive for strongyle and Parascaris spp. eggs, followed by Mini-FLOTAC and FECPAKG2. Regarding Anoplocephalidae, no significant difference in frequency of positive samples was observed between Mini-FLOTAC and sedimentation/flotation. Cohen’s κ values comparing individual methods with the combined result of all three methods revealed almost perfect agreement (κ ≥ 0.94) for sedimentation/flotation and strong agreement for Mini-FLOTAC (κ ≥ 0.83) for strongyles and Parascaris spp. For FECPAKG2, moderate and weak agreements were found for the detection of strongyle (κ = 0.62) and Parascaris (κ = 0.51) eggs, respectively. Despite higher sensitivity, the Mini-FLOTAC mean epg was significantly lower than that with FECPAKG2 due to samples with > 200 raw egg counts by sedimentation/flotation, while in samples with lower egg shedding epgs were higher with Mini-FLOTAC than with FECPAKG2. Conclusions For the simple detection of parasite eggs, for example, to treat foals infected with Parascaris spp., sedimentation/flotation is sufficient and more sensitive than the other two quantitative investigared in this study. Mini-FLOTAC is predicted to deliver more precise results in faecal egg count reduction tests due to higher raw egg counts. Finally, to identify animals with a strongyle epg above a certain threshold for treatment, FECPAKG2 delivered results comparable to Mini-FLOTAC. Grpahical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05266-y.
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Affiliation(s)
- Heike Boelow
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany.
| | - Eurion Thomas
- Techion UK, Peithyll Centre, Capel Dewi, Aberystwyth, SY23 3HU, Wales, UK
| | - Greg Mirams
- Techion New Zealand, Invermay Agriculture Centre, Block A, 176 Puddle Alley, Mosgiel, 9092, New Zealand
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
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The Use of Molecular Profiling to Track Equine Reinfection Rates of Cyathostomin Species Following Anthelmintic Administration. ANIMALS : AN OPEN ACCESS JOURNAL FROM MDPI 2021; 11:ani11051345. [PMID: 34065099 PMCID: PMC8150961 DOI: 10.3390/ani11051345] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/25/2021] [Accepted: 05/06/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary
Cyathostomins (small strongyles) are a multispecies group of intestinal parasites in horses and the main target of deworming efforts by horse owners. It is not known whether species of cyathostomins have individual responses to dewormers. The objective of this study was to identify differences between cyathostomin species in reemergence rates following commercial dewormer treatment. This study used gene sequencing to profile the presence/absence of cyathostomin species in fecal samples at 2-week intervals following deworming to determine how quickly each species reinfected horses. Moxidectin was found to be the most effective at slowing the overall reemergence of these parasites, followed by Ivermectin, then Pyrantel. Seven species were resistant to all three deworming products. This study demonstrates that dewormer sensitivity differs between cyathostomin species, which could lead to more targeted control measures. Abstract Cyathostomins are a multispecies parasite ubiquitous in Equids. Cyathostomins have developed resistance to all but one class of anthelmintics, but species-level sensitivity to anthelmintics has not been shown. This study measured reinfection rates of cyathostomin species following the administration of three commercial dewormers. Nine treated horses were compared with 90 untreated controls during June-September 2017–2019. Ivermectin (IVM) (n = 6), Moxidectin (MOX) (n = 8) or Pyrantel (PYR) (n = 8) were orally administered. Fecal samples were collected every 14 d for 98 d. Fecal egg count reductions (FECR) were calculated using a modified McMaster technique. Nineteen cyathostomin species were identified by 5.8S-ITS-2 profiling using amplicon sequencing. Data were analyzed in QIIME1 and R statistical software using presence/absence methods. MOX had the lowest numbers of species present over the time course, followed by PYR then IVM (7.14, 10.17, 11.09, respectively); however, FECR was fastest for PYR. The presence of seven species: Coronocyclus labiatus, Cyathostomum catinatum, Cyathostomum tetracanthum, Cylicocylus elongatus, Cylicodontophorus bicoronatus, Cylicostephanus minutus, and Cylicostephanus goldi were unaffected by treatment (p > 0.05) points to species-specific differences in dewormer sensitivity and environmental persistence. Identifying resistance patterns at the species level will enable mechanistic understandings of cyathostomin anthelmintic resistance and targeted approaches to control them.
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