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Home / Equine Research Bank / Vet Parasitol / Use of two in vitro methods for the detection of benzimidazo...
Veterinary parasitology1996; 65(1-2); 117-125; doi: 10.1016/0304-4017(96)00936-3

Use of two in vitro methods for the detection of benzimidazole resistance in equine small strongyles (Cyathostoma spp.).

Abstract: Ten stables were included in a study to evaluate two in vitro methods for the detection of anthelmintic resistance in cyathostomes by comparing a faecal egg count reduction test (FECRT) to a larval development assay (LDA) and an egg hatch assay (EHA). The LDA was used in seven stables and EHA in the last three. On the basis of FECR values, resistance to benzimidazoles was detected in eight of the ten small strongyle populations. Resistance to pyrantel pamoate and ivermectin was not detected. The mean concentrations that inhibited hatching in 50% of the eggs (EC50), using thiabendazole (TBZ) in an EHA, were 1.02 microM in resistant populations and 0.37 microM in susceptible or suspected resistant ones. In the LDA, TBZ concentrations preventing 50% development by first/second stage larvae to the third larval stage (LC50) were 3.8 times lower than EC50 values in resistant worm populations. Mean LC50 for morantel, levamisol, ivermectin monosaccharide and avermectin-B2 in small strongyle populations susceptible to pyrantel and ivermectin was 8.0 microM, 0.99 microM, 15.6 nM and 2.93 nM, respectively. Data on pyrantel and ivermectin resistant populations could not be obtained as no resistant populations were detected. This study concludes that in vitro tests may be useful as a supplement to FECRT for the detection of benzimidazole resistance in cyathostomes, even if reference populations to be used as controls in the assays were not available. It is suggested that EC50 values for TBZ > 0.6 microM in LDA and > 0.5 microM in EHA strongly indicate benzimidazole resistance in equine small strongyles.
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Publication Date: 1996-10-15 PubMed ID: 8916406DOI: 10.1016/0304-4017(96)00936-3Google Scholar: Lookup
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  • 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 explores the use of two laboratory methods for tracking how drug-resilient the Small Strongyles worm (Cyathostominae) has become. Ten stables were surveyed, using a faecal egg count reduction test (FECRT), a larval development assay (LDA) and an egg hatch assay (EHA), to compare the effectiveness of various anthelmintic drugs.

Study Design

  • The study involved ten stables, and assessed the resistance of cyathostomes, or small strongyles, to benzimidazoles, an antiparasitic medication.
  • In a practical approach, they used different tests across each stable, executing an LDA at seven stables and an EHA at the remaining three.
  • The researchers utilized a fecal egg count reduction test (FECRT) to measure the effectiveness of the drugs, by comparing the number of parasite eggs in feces before and after treatment.

Drug Resistance

  • Using the FECR values, the study found that eight out of ten small strongyles populations showed resistance to benzimidazoles.
  • On the other hand, the parasitic worms sampled did not show resistance to pyrantel pamoate and ivermectin, other common deworming medications.
  • This resistance was quantified by measuring the concentrations of the drugs that inhibited hatching in 50% of the eggs (EC50).

Resistance Measurements

  • For benzimidazoles-resistant populations, the average EC50 was 1.02 microM, while it was 0.37 microM for the populations that were either susceptible or suspected to be resistant.
  • The study used thiabendazole (TBZ) as a representative substance for benzimidazoles when performing their measurements.
  • In the LDA, TBZ concentrations that prevented 50% development from first or second stage larvae to the third larval stage were 3.8 times lower than the EC50 values in the resistant worm populations.

Results and Conclusion

  • The study could not obtain data on pyrantel and ivermectin-resistant populations, as no resistant populations were detected.
  • The research concluded that in vitro tests, such as LDA and EHA, are helpful supplementary tools to the FECRT in identifying benzimidazole resistance in cyathostomes.
  • The study suggests that EC50 values greater than 0.6 microM in LDA and more than 0.5 microM in EHA strongly indicate benzimidazole resistance in small strongyles.

Cite This Article

APA
Ihler CF, Bjørn H. (1996). Use of two in vitro methods for the detection of benzimidazole resistance in equine small strongyles (Cyathostoma spp.). Vet Parasitol, 65(1-2), 117-125. https://doi.org/10.1016/0304-4017(96)00936-3

Publication

Veterinary parasitology
ISSN: 0304-4017
NlmUniqueID: 7602745
Country: Netherlands
Language: English
Volume: 65
Issue: 1-2
Pages: 117-125

Researcher Affiliations

Ihler, C F
  • Department of Large Animal Clinical Sciences, Norwegian College of Veterinary Medicine, Oslo, Norway.
Bjørn, H

    MeSH Terms

    • Animals
    • Anthelmintics / therapeutic use
    • Benzimidazoles / therapeutic use
    • Drug Resistance
    • Feces / parasitology
    • Fenbendazole / therapeutic use
    • Horses
    • Larva
    • Mebendazole / therapeutic use
    • Parasite Egg Count
    • Strongyle Infections, Equine / drug therapy
    • Strongyloidea / growth & development
    • Strongyloidea / isolation & purification
    • Thiabendazole / therapeutic use

    Citations

    This article has been cited 5 times.
    1. Adediran OA, Uwalaka EC. Effectiveness Evaluation of Levamisole, Albendazole, Ivermectin, and Vernonia amygdalina in West African Dwarf Goats.. J Parasitol Res 2015;2015:706824.
      doi: 10.1155/2015/706824pubmed: 26579232google scholar: lookup
    2. 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
    3. von Samson-Himmelstjerna G, Coles GC, Jackson F, Bauer C, Borgsteede F, Cirak VY, Demeler J, Donnan A, Dorny P, Epe C, Harder A, Höglund J, Kaminsky R, Kerboeuf D, Küttler U, Papadopoulos E, Posedi J, Small J, Várady M, Vercruysse J, Wirtherle N. Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes.. Parasitol Res 2009 Sep;105(3):825-34.
      doi: 10.1007/s00436-009-1466-1pubmed: 19452165google scholar: lookup
    4. 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
    5. Königová A, Várady M, Corba J. Comparison of in vitro methods and faecal egg count reduction test for the detection of benzimidazole resistance in small strongyles of horses.. Vet Res Commun 2003 May;27(4):281-8.
      doi: 10.1023/a:1024079907895pubmed: 12872828google scholar: lookup
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