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Home / Equine Research Bank / Equine Vet J / Faecal worm egg count analysis for targeting anthelmintic tr...
Equine veterinary journal2013; 46(2); 139-145; doi: 10.1111/evj.12199

Faecal worm egg count analysis for targeting anthelmintic treatment in horses: points to consider.

Abstract: Equine gastrointestinal nematodes are ubiquitous; in horses that graze contaminated pasture and that are not treated appropriately, large numbers of worms can accumulate, which can lead to serious clinical disease. Nematode control has traditionally followed interval treatment regimens, which involve regular anthelmintic administration to all horses based on the strongyle egg reappearance periods of each drug, usually defined around the time of licensing. Interval treatment programmes have resulted in substantial reductions in large strongyle disease, but have made major contributions to the development of anthelmintic resistance, particularly in cyathostomins. Cyathostomin resistance to 2 of the 3 available anthelmintic classes is widespread, and resistance to both classes in single populations is not uncommon. Reduced efficacy of the most commonly used macrocyclic lactone anthelmintics, as measured by shortened egg reappearance periods after treatment, is emerging in cyathostomins. Macrocyclic lactone resistance is also now commonly reported in Parascaris equorum on stud farms. Faecal worm egg counts (FWEC) are increasingly being used as part of targeted approaches to parasite control, whereby only those horses with moderate to high FWEC within a group are treated with an anthelmintic. The objective of this approach is to reduce environmental contamination, while leaving a proportion of the worm population in some horses unexposed to selection pressure for anthelmintic resistance. This article reviews recent findings in equine parasitology research that will underpin guidelines for control, with a particular focus on how to optimise the value of FWEC methodologies and anthelmintic efficacy analyses.
© 2013 EVJ Ltd.
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Publication Date: 2013-12-10 PubMed ID: 24131301DOI: 10.1111/evj.12199Google Scholar: Lookup
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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 discusses the issue of anthelmintic resistance in common gastrointestinal nematodes found in horses, and suggests the use of faecal worm egg counts (FWEC) and strategic treatment to control the nematode populations without promoting resistance.

Nematode Infestations in Horses

  • The study begins by highlighting the prevalence of gastrointestinal nematodes in horses, especially those that graze contaminated pasture. Without proper treatment, these worms can multiply and cause serious health problems.
  • Until now, most treatment programs for nematodes have followed interval treatment regimens, which involve administering anthelmintics to all horses on a regular basis based on the egg reappearance periods of the worms, detected post-treatment.

Anthelmintic Resistance

  • The paper points out that while interval treatment programs have led to significant reductions in large strongyle disease, they have also contributed to the emergence of widespread anthelmintic resistance, particularly in a type of nematode known as cyathostomins.
  • The study reveals that cyathostomins have developed resistance to two out of three available classes of anthelmintic drugs, with instances of resistance to both classes in a single population not being uncommon.
  • Furthermore, the effectiveness of macrocyclic lactone anthelmintics, a commonly used drug class, has been diminishing due to emerging resistance in cyathostomins.
  • The study also reports growing resistance to macrocyclic lactone drugs in another worm species, Parascaris equorum; commonly found in stud farms.

Strategic Parasite Control through FWEC

  • The paper proposes the use of faecal worm egg counts (FWEC) as a part of targeted approaches for parasite control. In this method, only those horses with moderate to high FWEC levels are treated with an anthelmintic.
  • The aim of this strategy is to reduce environmental contamination by the nematodes, while also leaving some of the worm populations in certain horses untreated. This leaves a portion of the worm population unexposed to the drugs, thereby reducing the selection pressure for anthelmintic resistance.
  • The paper then reviews recent findings in equine parasitology research which could be used to develop guidelines for controlling nematode infestations in horses, with a primary focus on the optimisation of FWEC methodologies and improving the analyzation of anthelmintic efficacy.

Cite This Article

APA
Lester HE, Matthews JB. (2013). Faecal worm egg count analysis for targeting anthelmintic treatment in horses: points to consider. Equine Vet J, 46(2), 139-145. https://doi.org/10.1111/evj.12199

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 46
Issue: 2
Pages: 139-145

Researcher Affiliations

Lester, H E
  • Moredun Research Institute, Edinburgh, UK.
Matthews, J B

    MeSH Terms

    • Animals
    • Anthelmintics / administration & dosage
    • Anthelmintics / therapeutic use
    • Horse Diseases / drug therapy
    • Horse Diseases / parasitology
    • Horses
    • Parasite Egg Count
    • Parasitic Diseases, Animal / drug therapy

    Citations

    This article has been cited 20 times.
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