Authors

J McIntyre⁴; K Maitland⁴; D Berger³; A Morrison¹; D Bartley¹; K Bull²; E Devaney⁴; R Laing⁴; SR Doyle³;  ¹ Moredun Research Institute, UK;  ² University of Bristol, UK;  ³ Wellcome Sanger Institute, UK;  ⁴ School of Biodiversity, One Health and Comparative Medicine, University of Glasgow, UK

Discussion

Ivermectin is a powerful endectocide, used to control infections in both humans and animals. However, widespread resistance to this anthelmintic has arisen, particularly in helminths of importance to the livestock industry. The development of anthelmintic resistance by the small ruminant nematode Teladorsagia circumcincta, a significant pathogen of growing lambs in the UK and in other temperate climates, threatens food security. We seek to identify the genetic causes of ivermectin resistance in T. circumcincta. To do so, we sought to improve the primary tool available to us for this work: the genome annotation and assembly of T. circumcincta, which is now largely contained within six large scaffolds corresponding to the five autosomes and the sex chromosome. Using whole genome sequencing of larvae sampled pre- and post-ivermectin treatment on UK farms, together with a reanalysis of a genetic cross, I will show how this new assembly has enabled us to identify a locus under selection by ivermectin on Chromosome 5, and compare this with that found in the related abomasal nematode Haemonchus contortus. I will consider some of the key findings and the outstanding questions still remaining.