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Home / Equine Research Bank / Vet Parasitol / Cylicocyclus species predominate during shortened egg reappe...
Veterinary parasitology2014; 206(3-4); 246-252; doi: 10.1016/j.vetpar.2014.10.004

Cylicocyclus species predominate during shortened egg reappearance period in horses after treatment with ivermectin and moxidectin.

Abstract: The normal time interval between treatment of horses with a macrocyclic lactone (ML) and reappearance of strongyle eggs in the feces, or 'Egg Reappearance Period (ERP)', is at its shortest 8 weeks for ivermectin (IVM) and 12 weeks for moxidectin (MOX). Nowadays, it is not uncommon to find shorter ERPs, potentially indicating the beginning of the development of drug resistance. Whether all cyathostomin species contribute equally to a shortened ERP is not known. In the present study a Reverse Line Blot (RLB) on individual infective larvae was used to compare species composition before and after ML-treatment in horses with either a normal or a shortened ERP. Species composition was determined for a total of 21 horses on 4 farms and was based on differentiation of approximately 40 larvae per horse per sampling day. After IVM treatment the shortest ERP was found to be 28-42 days. After MOX treatment the shortest ERP was found to be 42-56 days. The RLB showed that early egg shedding was dominated by species of the genus Cylicocyclus (Cyc.) (Cyc. ashworthi, Cyc. insigne, Cyc. leptostomum and Cyc. nassatus). Before treatment, species composition was generally more diverse with species from several other genera also present. Interestingly, on the farm with the overall shortest ERP and where all horses showed a shortened ERP, more species/genera were present during early egg excretion than on other farms. Results suggest that cyathostomin species within the genus Cylicocyclus contribute to a shortened ERP more than species from other genera. However, if shortening of ERP overall becomes more pronounced and widespread within a farm, species from other genera will also be present during early egg shedding.
Copyright © 2014 Elsevier B.V. All rights reserved.
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Publication Date: 2014-12-03 PubMed ID: 25458565DOI: 10.1016/j.vetpar.2014.10.004Google 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.

This research paper investigates why there has been a decrease in the time interval between treatment of horses with anti-parasite drugs and reemergence of parasite eggs. Researchers found that species within the genus Cylicocyclus are more likely to contribute to this shortened period than genera from other species.

Objective of the Research

  • The aim of this study was to understand why there is a decrease in the ‘Egg Reappearance Period’ (ERP) – the interval between the administration of a macrocyclic lactone (ML) drug to horses and the reemergence of strongyle parasite eggs.
  • The researchers wanted to determine if all cyathostomin species contribute equally to this decreased ERP.

Methods

  • Using a Reverse Line Blot (RLB) technique, researchers compared the species composition in the feces of horses before and after ML treatment.
  • The study was conducted on 21 horses across 4 farms.
  • Approximately 40 larvae were analyzed per horse per day to determine species composition.

Key Findings

  • The shortest ERP observed after treatment with ivermectin (IVM) was between 28-42 days, while with moxidectin (MOX), it was between 42-56 days.
  • Species of the genus Cylicocyclus were predominant in early egg shedding after drug treatment.
  • Prior to treatment, species composition in the feces of the horses was more diverse, including species from other genera.
  • On the farm with the overall shortest ERP, more species/genera were present during early egg excretion than on other farms.

Conclusion

  • The study concluded that species within the genus Cylicocyclus are likely to be more responsible for the observed shortened ERP, but as the shortening of ERP becomes more pronounced across a farm, species from other genera also contribute to early egg shedding.

Cite This Article

APA
van Doorn DC, Ploeger HW, Eysker M, Geurden T, Wagenaar JA, Kooyman FN. (2014). Cylicocyclus species predominate during shortened egg reappearance period in horses after treatment with ivermectin and moxidectin. Vet Parasitol, 206(3-4), 246-252. https://doi.org/10.1016/j.vetpar.2014.10.004

Publication

Veterinary parasitology
ISSN: 1873-2550
NlmUniqueID: 7602745
Country: Netherlands
Language: English
Volume: 206
Issue: 3-4
Pages: 246-252

Researcher Affiliations

van Doorn, D C K
    Ploeger, H W
      Eysker, M
        Geurden, T
          Wagenaar, J A
            Kooyman, F N J

              MeSH Terms

              • Animals
              • Anthelmintics / therapeutic use
              • Drug Resistance
              • Feces / parasitology
              • Horse Diseases / drug therapy
              • Horse Diseases / parasitology
              • Horses
              • Ivermectin / therapeutic use
              • Larva
              • Macrolides / therapeutic use
              • Ovum / drug effects
              • Parasite Egg Count / veterinary
              • Strongyle Infections, Equine / drug therapy
              • Strongyle Infections, Equine / parasitology
              • Strongyloidea / drug effects
              • Strongyloidea / genetics
              • Strongyloidea / isolation & purification

              Citations

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