Increasing resistance to multiple anthelmintic classes in gastrointestinal nematodes on sheep farms in southwest England

Bull, Katie, Glover, Mike J, Vineer, Hannah Rose ORCID: 0000-0002-1488-0315 and Morgan, Eric R (2022) Increasing resistance to multiple anthelmintic classes in gastrointestinal nematodes on sheep farms in southwest England. VETERINARY RECORD, 190 (11). e1531-.

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Official URL: http://dx.doi.org/10.1002/vetr.1531

Abstract

<h4>Background</h4>Anthelmintic resistance (AR) in gastrointestinal nematodes (GIN) is increasing globally, and farmers are encouraged to adopt sustainable control measures. Haemonchus contortus is increasingly reported in the UK, potentially complicating effective GIN control.<h4>Methods</h4>Faecal egg count reduction tests (FECRT) were conducted on 13 farms in north Devon, England, UK in 2016. Relative abundance of H. contortus was quantified using peanut agglutinin staining and used to estimate faecal egg count reduction percentages (FECR%) using the eggCounts R package.<h4>Results</h4>On average, farms had GIN resistance to three anthelmintic classes. No farms had susceptibility to all anthelmintics tested. AR was more prevalent in 2016 than on the same farms in 2013. H. contortus was present on 85% of the farms tested and comprised on average 6% (0%-52%) of GIN eggs before treatment. Resistance or suspected resistance to all anthelmintics tested was observed in this species on different farms.<h4>Conclusion</h4>The results demonstrate diversity of AR profiles on farms, apparent progression of AR within a 3-year period, and challenges detecting AR in mixed-species infections. Where possible, interpretation of mixed-species FECRT should take into account the relative abundance of species pre- and post-treatment to identify pragmatic treatment options targeting individual genera.

Item Type:	Article
Uncontrolled Keywords:	anthelmintic resistance, faecal egg count reduction tests, Haemonchus contortus, sheep
Divisions:	Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User:	Symplectic Admin
Date Deposited:	30 Jun 2022 14:41
Last Modified:	18 Jan 2023 20:56
DOI:	10.1002/vetr.1531
Open Access URL:	https://doi.org/10.1002/vetr.1531
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3157508