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The genetic basis and monitoring of anthelmintic resistance in the pathogenic endoparasites of small ruminants

Baltrusis, Paulius (2022). The genetic basis and monitoring of anthelmintic resistance in the pathogenic endoparasites of small ruminants. Diss. (sammanfattning/summary) Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880
ISBN 978-91-7760-951-3
eISBN 978-91-7760-952-0
[Doctoral thesis]

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By parasitizing livestock, gastrointestinal nematodes inflict a significant monetaryburden on the producers and compromise animal health as well as the sustainabilityof animal farming systems. To date, the most reliable way to control parasiticinfections in grazing livestock is through the use of anthelmintic drugs. However,decades of use have led to the parasites developing resistance. In small ruminants,one of the most pathogenic and prone to developing resistance is the parasiteHaemonchus contortus. This thesis aims to describe our most recent efforts to updatethe current knowledge on anthelmintic resistance in sheep nematodes by studying H.contortus in order to i) develop molecular tools to screen for mutations associatedwith resistance, ii) use these tools to carry out country-wide screenings for resistancemutations on Swedish sheep farms as well as iii) investigate potential, resistanceassociatedcandidate loci and genes through both the single-candidate and the genome-wide comparison approaches. We developed a sensitive droplet digital PCRbasedtool to screen for benzimidazole resistance-associated mutations and subsequentlyfound extremely high frequencies of the F200Y mutation but not F167Y inSwedish, field isolates of H. contortus collected over 6 years from 67 sheep farms.We also investigated the 63bp deletion in the hco-acr-8 as well as its role as a possiblemarker for levamisole resistance and found it to correlate with (but be an unreliablepredictor of) the resistant phenotype. Finally, we carried out a genome-widecomparison study between the ivermectin treated and untreated population andfound a region in chromosome V to show signs of recent selection, indicating theimportance of that locus in the development of ivermectin resistance in sheep nematodes.

Authors/Creators:Baltrusis, Paulius
Title:The genetic basis and monitoring of anthelmintic resistance in the pathogenic endoparasites of small ruminants
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2022
Number of Pages:98
Publisher:Swedish University of Agricultural Sciences
ISBN for printed version:978-91-7760-951-3
ISBN for electronic version:978-91-7760-952-0
Publication Type:Doctoral thesis
Article category:Other scientific
Version:Published version
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Genetics (medical genetics to be 30107 and agricultural genetics to be 40402)
Keywords:benzimidazole, levamisole, ivermectin, anthelmintic resistance, F200Y, hco-acr-8, droplet digital PCR, sequencing, GWAS, genome
Permanent URL:
ID Code:28735
Faculty:VH - Faculty of Veterinary Medicine and Animal Science
Department:(VH) > Department of Biomedical Science and Veterinary Public Health
Deposited By: SLUpub Connector
Deposited On:02 Sep 2022 07:23
Metadata Last Modified:02 Sep 2022 07:31

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