TY - JOUR
T1 - Benzimidazole-resistance associated mutation in Haemonchus contortus in Norwegian sheep, as detected by droplet digital PCR
AU - Gravdal, Maiken
AU - Woolsey, Ian D.
AU - Robertson, Lucy J.
AU - Hoglund, Johan
AU - Chartier, Christophe
AU - Stuen, Snorre
N1 - Publisher Copyright:
© 2023 The Authors
PY - 2023
Y1 - 2023
N2 - The aim of this study was to investigate the occurrence of benzimidazole-resistant Haemonchus contortus in Norwegian sheep flocks. Screening was based on detection of one of the resistance-conferring mutations in the beta tubulin isotype 1 gene (F200Y, TAC) in larvae (L3) cultivated from H. contortus eggs from naturally infected sheep. Faecal samples were collected in 2021/2022 from flocks in the northern (n = 34), central (n = 7), eastern (n = 40), southern (n = 1), and western (n = 87) areas of Norway. In total, samples were taken from 169 flocks (spring-ewes samples: 167, autumn-lambs samples: 134). Individual faecal samples were collected from 10 randomly selected ewes (spring) and 10 randomly selected lambs (autumn) in each flock. Faecal samples collected from each flock on each occasion were pooled (lamb and ewe samples pooled separately) and cultured for L3 development. After harvest of larvae (Baermann method), DNA was extracted and then analysed using droplet digital PCR with primer/probe sets targeting the BZ-associated F200Y (TAC) mutation. Haemonchus was found in 60% (80/134) of samples from lambs, and in 63% (106/167) from ewes. Among these, the F200Y mutation was detected in 73% (58/80) of larval samples from lambs and 69% (73/106) of larval samples from ewes, respectively. Although regional differences were evident, the mutation was detected in all areas indicating a widespread distribution and a strong potential for an increasing problem with treatmentresistant haemonchosis in Norwegian sheep flocks.
AB - The aim of this study was to investigate the occurrence of benzimidazole-resistant Haemonchus contortus in Norwegian sheep flocks. Screening was based on detection of one of the resistance-conferring mutations in the beta tubulin isotype 1 gene (F200Y, TAC) in larvae (L3) cultivated from H. contortus eggs from naturally infected sheep. Faecal samples were collected in 2021/2022 from flocks in the northern (n = 34), central (n = 7), eastern (n = 40), southern (n = 1), and western (n = 87) areas of Norway. In total, samples were taken from 169 flocks (spring-ewes samples: 167, autumn-lambs samples: 134). Individual faecal samples were collected from 10 randomly selected ewes (spring) and 10 randomly selected lambs (autumn) in each flock. Faecal samples collected from each flock on each occasion were pooled (lamb and ewe samples pooled separately) and cultured for L3 development. After harvest of larvae (Baermann method), DNA was extracted and then analysed using droplet digital PCR with primer/probe sets targeting the BZ-associated F200Y (TAC) mutation. Haemonchus was found in 60% (80/134) of samples from lambs, and in 63% (106/167) from ewes. Among these, the F200Y mutation was detected in 73% (58/80) of larval samples from lambs and 69% (73/106) of larval samples from ewes, respectively. Although regional differences were evident, the mutation was detected in all areas indicating a widespread distribution and a strong potential for an increasing problem with treatmentresistant haemonchosis in Norwegian sheep flocks.
KW - Anthelmintic resistance
KW - Droplet digital PCR
KW - Gastrointestinal nematodes
KW - Haemonchus contortus
KW - Parasite control
KW - Sheep
KW - Anthelmintic resistance
KW - Droplet digital PCR
KW - Gastrointestinal nematodes
KW - Haemonchus contortus
KW - Parasite control
KW - Sheep
UR - https://res.slu.se/id/publ/128422
U2 - 10.1016/j.vprsr.2023.100938
DO - 10.1016/j.vprsr.2023.100938
M3 - Journal article
C2 - 37935539
AN - SCOPUS:85173529939
SN - 2405-9390
VL - 46
JO - Veterinary Parasitology: Regional Studies and Reports
JF - Veterinary Parasitology: Regional Studies and Reports
M1 - 100938
ER -