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Veterinary parasitology2002; 106(4); 331-343; doi: 10.1016/s0304-4017(02)00093-6

Evaluation of tests for anthelmintic resistance in cyathostomes.

Abstract: Resistance, especially to the anthelmintic benzimidazoles (BZ), has been reported in horse cyathostomes world-wide. Diagnosis of resistance has traditionally been made by faecal egg count reduction (FECR) trials, however, this technique has limitations. Some of the shortcomings may be resolved by refining the test or by using an in vitro test. FECR tests and the larval development assay (LDA) were performed on adult horses held on 15 different horse properties across a wide geographical area of NSW, Australia. FECR were measured before and 10-14 after days treatment with oxibendazole (OBZ), morantel (MOR) or ivermectin (IVM) at recommended dose rates. Eight properties were rejected following low pre-treatment egg counts, leaving seven in the study. On these, the majority of larvae recovered from faecal cultures were cyathostomes. Using a definition of resistance as a FECR of <90%, resistance to OBZ was present on six properties and to MOR on two properties. Resistance to IVM was not detected. An alternative method of calculating FECR based on individual horse egg counts pre- and post-treatment was developed and results from the same properties compared with the results of the LDA. For example, for the BZ, correlation coefficients of values of lethal concentration to kill 50% of population (LC50) on LDA and FECR percentages were -0.536 before and -0.704 after OBZ treatment. We conclude that the LDA has the potential to be a single visit test for detection of anthelmintic resistance in horse cyathostomes but requires further investigation and standardisation.
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Publication Date: 2002-06-25 PubMed ID: 12079739DOI: 10.1016/s0304-4017(02)00093-6Google Scholar: Lookup
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  • Evaluation Study
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article speaks about the concerning emergence of resistance to anthelmintic drugs, particularly benzimidazoles (BZ), in horse cyathostomes worldwide. The article describes an evaluation of different methods to detect such resistance, highlighting the potential of the Larval Development Assay (LDA) as a promising single-visit test that might outperform traditional methods.

Objective of the Research

  • The main objective was to evaluate the current tests used for identifying drug resistance in cyathostomes, a type of parasitic worm in horses, especially resistance to benzimidazoles, a class of anthelmintic drugs. The standard diagnostic tool, faecal egg count reduction (FECR) tests, have shown some limitations and potential inaccuracies. Therefore, an alternative in vitro test, the Larval Development Assay (LDA), was considered and tested in this study.

Methodology

  • The study was conducted on adult horses residing on 15 different properties spread across New South Wales, Australia. The various procedures involved in the research include conducting FECR tests and LDA tests on these horses, with measurements taking place before and 10-14 days after treatment with specific anthelmintic drugs like oxibendazole, morantel, and ivermectin.
  • Initial results from the FECR test were considered and low pre-treatment egg count properties were excluded from the study, narrowing the focus to seven properties which mostly revealed cyathostome larvae.

Findings

  • The researchers observed and defined resistance to anthelmintic drugs as a faecal egg count reduction (FECR) of less than 90%. By using this parameter, they discovered resistance to oxibendazole on six properties and to morantel on two properties.
  • No resistance to ivermectin was found.
  • An alternative calculation method for FECR, based on individual horse egg counts pre- and post-treatment was also developed and tested within the study. The correlation coefficients of values between lethal concentration to kill 50% of the population during the LDA test and FECR percentages were comparatively examined, particularly before and after treatment with Benzimidazoles.

Conclusions

  • Based on their findings, the researchers concluded that the Larval Development Assay (LDA) could potentially serve as a more effective single visit detection mechanism for anthelmintic resistance in horse cyathostomes. However, they also indicated that further investigations and standardization studies would be needed to fully validate this diagnostic method.

Cite This Article

APA
Pook JF, Power ML, Sangster NC, Hodgson JL, Hodgson DR. (2002). Evaluation of tests for anthelmintic resistance in cyathostomes. Vet Parasitol, 106(4), 331-343. https://doi.org/10.1016/s0304-4017(02)00093-6

Publication

Veterinary parasitology
ISSN: 0304-4017
NlmUniqueID: 7602745
Country: Netherlands
Language: English
Volume: 106
Issue: 4
Pages: 331-343

Researcher Affiliations

Pook, J F
  • Faculty of Veterinary Science, University of Sydney, 2006, Sydney, Australia
Power, M L
    Sangster, N C
      Hodgson, J L
        Hodgson, D R

          MeSH Terms

          • Animals
          • Anthelmintics / therapeutic use
          • Benzimidazoles / therapeutic use
          • Body Weight
          • Drug Resistance
          • Feces / parasitology
          • Horse Diseases / drug therapy
          • Horse Diseases / parasitology
          • Horses
          • New South Wales
          • Parasite Egg Count / veterinary
          • Random Allocation
          • Strongylida Infections / drug therapy
          • Strongylida Infections / parasitology
          • Strongylida Infections / veterinary
          • Strongyloidea / drug effects
          • Strongyloidea / growth & development

          Citations

          This article has been cited 16 times.
          1. Abbas G, Ghafar A, Hurley J, Bauquier J, Beasley A, Wilkes EJA, Jacobson C, El-Hage C, Cudmore L, Carrigan P, Tennent-Brown B, Gauci CG, Nielsen MK, Hughes KJ, Beveridge I, Jabbar A. Cyathostomin resistance to moxidectin and combinations of anthelmintics in Australian horses. Parasit Vectors 2021 Dec 4;14(1):597.
            doi: 10.1186/s13071-021-05103-8pubmed: 34863271google scholar: lookup
          2. Elmeligy E, Abdelbaset A, Elsayed HK, Bayomi SA, Hafez A, Abu-Seida AM, El-Khabaz KAS, Hassan D, Ghandour RA, Khalphallah A. Oxidative stress in Strongylus spp. infected donkeys treated with piperazine citrate versus doramectin. Open Vet J 2021 Apr-Jun;11(2):238-250.
            doi: 10.5455/OVJ.2021.v11.i2.8pubmed: 34307081google scholar: lookup
          3. Saeed MA, Beveridge I, Abbas G, Beasley A, Bauquier J, Wilkes E, Jacobson C, Hughes KJ, El-Hage C, O'Handley R, Hurley J, Cudmore L, Carrigan P, Walter L, Tennent-Brown B, Nielsen MK, Jabbar A. Systematic review of gastrointestinal nematodes of horses from Australia. Parasit Vectors 2019 Apr 29;12(1):188.
            doi: 10.1186/s13071-019-3445-4pubmed: 31036059google scholar: lookup
          4. Zhang JL, Si HF, Zhou XZ, Shang XF, Li B, Zhang JY. High prevalence of fasciolosis and evaluation of the efficacy of anthelmintics against Fasciola hepatica in buffaloes in Guangxi, China. Int J Parasitol Parasites Wildl 2019 Apr;8:82-87.
            doi: 10.1016/j.ijppaw.2018.12.010pubmed: 30671343google scholar: lookup
          5. Fischer JK, Hinney B, Denwood MJ, Traversa D, von Samson-Himmelstjerna G, Clausen PH. Efficacy of selected anthelmintic drugs against cyathostomins in horses in the federal state of Brandenburg, Germany. Parasitol Res 2015 Dec;114(12):4441-50.
            doi: 10.1007/s00436-015-4685-7pubmed: 26337266google scholar: lookup
          6. Brockwell YM, Elliott TP, Anderson GR, Stanton R, Spithill TW, Sangster NC. Confirmation of Fasciola hepatica resistant to triclabendazole in naturally infected Australian beef and dairy cattle. Int J Parasitol Drugs Drug Resist 2014 Apr;4(1):48-54.
            doi: 10.1016/j.ijpddr.2013.11.005pubmed: 24596668google scholar: lookup
          7. Lind EO, Christensson D. Anthelmintic efficacy on Parascaris equorum in foals on Swedish studs. Acta Vet Scand 2009 Nov 22;51(1):45.
            doi: 10.1186/1751-0147-51-45pubmed: 19930608google scholar: lookup
          8. Lake SL, Matthews JB, Kaplan RM, Hodgkinson JE. Determination of genomic DNA sequences for beta-tubulin isotype 1 from multiple species of cyathostomin and detection of resistance alleles in third-stage larvae from horses with naturally acquired infections. Parasit Vectors 2009 Sep 25;2 Suppl 2(Suppl 2):S6.
            doi: 10.1186/1756-3305-2-S2-S6pubmed: 19778467google scholar: lookup
          9. Lind EO, Kuzmina T, Uggla A, Waller PJ, Höglund J. A field study on the effect of some anthelmintics on cyathostomins of horses in sweden. Vet Res Commun 2007 Jan;31(1):53-65.
            doi: 10.1007/s11259-006-3402-5pubmed: 17186406google scholar: lookup
          10. Cirak VY, Güleğen E, Bauer C. Benzimidazole resistance in cyathostomin populations on horse farms in western Anatolia, Turkey. Parasitol Res 2004 Aug;93(5):392-5.
            doi: 10.1007/s00436-004-1143-3pubmed: 15221466google scholar: lookup
          11. Jamshidpour R, Nabavi R, Moadab H, Rezaie F, Chale AC, Sargison N. Evaluation of Benzimidazole Resistance in Equine Cyathostomins in the Kermanshah Province of Iran Using Coprological Analysis and Allele-Specific PCR. Iran J Parasitol 2025 Jul-Sep;20(3):389-399.
            doi: 10.18502/ijpa.v20i3.19614pubmed: 41181201google scholar: lookup
          12. Abbas G, Nielsen MK, E-Hage C, Ghafar A, Beveridge I, Bauquier J, Beasley A, Wilkes EJA, Carrigan P, Cudmore L, Jacobson C, Hughes KJ, Jabbar A. Recent advances in intestinal helminth parasites of horses in the Asia-Pacific region: Current trends, challenges and future directions. Int J Parasitol Drugs Drug Resist 2025 Dec;29:100622.
            doi: 10.1016/j.ijpddr.2025.100622pubmed: 41135277google scholar: lookup
          13. Zavala D, Rojas-Moncada J, Hobán C, Torrel T, Vargas-Rocha L. Low efficacy of levamisole for Ascaridia galli control in experimentally infected poultry: first report in Cajamarca (Peru). Vet Res Commun 2025 Sep 24;49(6):327.
            doi: 10.1007/s11259-025-10868-9pubmed: 40991095google scholar: lookup
          14. Beasley A, Abbas G, Hughes K, El-Hage C, Jacobson C, Bauquier J, Wilkes E, Carrigan P, Cudmore L, Hurley J, Beveridge I, Nielsen M, Jabbar A. Australian guidelines for equine internal parasite management. Aust Vet J 2025 Apr;103(4):151-158.
            doi: 10.1111/avj.13424pubmed: 39837536google scholar: lookup
          15. Abbas G, Stevenson MA, Bauquier J, Beasley A, Jacobson C, El-Hage C, Wilkes EJA, Carrigan P, Cudmore L, Hurley J, Beveridge I, Nielsen MK, Hughes KJ, Jabbar A. Assessment of worm control practices recommended by equine veterinarians in Australia. Front Vet Sci 2023;10:1305360.
            doi: 10.3389/fvets.2023.1305360pubmed: 38026649google scholar: lookup
          16. Nielsen MK. Anthelmintic resistance in equine nematodes: Current status and emerging trends. Int J Parasitol Drugs Drug Resist 2022 Dec;20:76-88.
            doi: 10.1016/j.ijpddr.2022.10.005pubmed: 36342004google scholar: lookup
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