Searching for ivermectin resistance in Dutch horses.
Abstract: A study was conducted to evaluate the occurrence of resistance against, in particular, ivermectin in cyathostomins in the Netherlands. Seventy horse farms were visited between October 2007 and November 2009. In initial screening, faecal samples were collected 2 weeks after deworming with either ivermectin, moxidectin or doramectin. Pooled faecal samples from a maximum of 10 horses were examined for worm eggs using a modified McMaster technique and for worm larvae after faecal larval cultures. In total 931 horses were involved. On 15 of 70 farms eggs and/or larvae were found. On 8 of these 15 farms a FECRT with ivermectin was performed on 43 horses. Efficacy of ivermectin against cyathostomins of 93% was found in one animal on one farm. Additionally, the strategies and efforts of the horse owners to control cyathostomins, as well as risk factors for the development of macrocyclic lactone resistance were evaluated with a questionnaire. Strikingly, many responders indicated that the control of cyathostomins in horses is achieved through very frequent deworming. Fourteen percent of these owners deworm seven times per year or more. On 34% of the 70 farms treatment was repeated within the Egg Reappearance Period of a product.
Copyright © 2011 Elsevier B.V. All rights reserved.
Publication Date: 2011-09-28 PubMed ID: 21996004DOI: 10.1016/j.vetpar.2011.09.028Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigated the potential development of ivermectin resistance amongst cyathostomins (a type of intestinal parasite) in horses in the Netherlands, which involved sampling and testing from horses in 70 farms over a period of two years.
Research Methodology
- The study was conducted on 70 horse farms across the Netherlands, spanning from October 2007 to November 2009.
- The team collected faecal samples from horses two weeks after they were dewormed. Deworming agents used included ivermectin, moxidectin, and doramectin.
- Pooled faecal samples from up to 10 horses were checked for worm eggs using a modified McMaster technique – a common method for determining parasite load in faecal matter. The samples were also checked for worm larvae after being cultured.
- In total, 931 horses across the farms were involved in the study.
Findings
- On 15 out of the 70 horse farms visited, the presence of worm eggs and/or larvae were found.
- Specifically, a Fecal Egg Count Reduction Test (FECRT) with ivermectin was performed on 43 horses across 8 of these 15 farms, in which only one animal on a singular farm showed 93% efficacy of ivermectin against cyathostomins.
- This suggests potential resistance against ivermectin in the cyathostomins found in this particular animal, given the reduced effectiveness of the deworming agent.
Horse Owner Questionnaire
- As part of the study, the researchers also conducted a questionnaire with horse owners to assess their strategies and efficacy in controlling cyathostomins, and to identify potential risk factors leading to the development of resistance against macrocyclic lactones – a class of deworming agents including ivermectin.
- Roughly 14% of respondents claimed to deworm their horses seven times a year or more.
- Additionally, on approximately 34% of the 70 farms surveyed, deworming treatment was repeated within the Egg Reappearance Period (ERP) of a product – this is the time period in which eggs reappear in a horse’s faeces after a deworming treatment is applied.
- Very frequent deworming and repeat treatment within the ERP may contribute to the development of deworming agent resistance amongst cyathostomins.
Cite This Article
APA
van Doorn DC, Eysker M, Kooyman FN, Wagenaar JA, Ploeger HW.
(2011).
Searching for ivermectin resistance in Dutch horses.
Vet Parasitol, 185(2-4), 355-358.
https://doi.org/10.1016/j.vetpar.2011.09.028 Publication
Researcher Affiliations
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands. d.c.k.vanDoorn@uu.nl
MeSH Terms
- Animals
- Anthelmintics / pharmacology
- Anthelmintics / therapeutic use
- Drug Resistance
- Helminthiasis, Animal / drug therapy
- Helminthiasis, Animal / epidemiology
- Helminthiasis, Animal / parasitology
- Helminths / drug effects
- Horse Diseases / drug therapy
- Horse Diseases / epidemiology
- Horse Diseases / parasitology
- Horses
- Ivermectin / pharmacology
- Ivermectin / therapeutic use
- Netherlands / epidemiology
- Risk Factors
- Surveys and Questionnaires
Citations
This article has been cited 3 times.- Papini RA, Orsetti C, Sgorbini M. A Controlled Study on Efficacy and Egg Reappearance Period of Ivermectin in Donkeys Naturally Infected with Small Strongyles. Helminthologia 2020 Jun 1;57(2):163-170.
- Zak A, Siwinska N, Slowikowska M, Borowicz H, Kubiak K, Hildebrand J, Popiolek M, Niedzwiedz A. Searching for ivermectin resistance in a Strongylidae population of horses stabled in Poland. BMC Vet Res 2017 Jul 3;13(1):210.
- Schneider S, Pfister K, Becher AM, Scheuerle MC. Strongyle infections and parasitic control strategies in German horses - a risk assessment. BMC Vet Res 2014 Nov 12;10:262.
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