Unravelling the mechanisms of resistance to the macrocyclic lactones in the sheep scab mite, Psoroptes ovis

Project Details

Description

Sheep scab, caused by infestation with the ectoparasitic mite Psoroptes ovis, is highly contagious, causing intense pruritus and represents a major welfare and economic concern for UK livestock production. Sheep scab costs the UK livestock industry between £80-202M per annum and disease control strategies rely upon a limited number of chemotherapeutic compounds, the sustainability of which is limited due to issues of chemical residues, eco-toxicity and emerging acaricide resistance. The continued use of organophosphate (OP) based sheep dips is under threat due to safety concerns for both operators and the environment. The only other method of control is the macrocyclic lactone (ML) injectables. However, these are heavily relied upon for the control of gastrointestinal nematodes in sheep and cattle, and the overreliance on a single class of drugs for a range of parasite species is the perfect recipe for the development of further drug resistance, leading to a potentially disastrous scenario for the UK farming industry. Perhaps of more concern are the recent identification of populations of P. ovis mites with confirmed resistance to all classes of the MLs, with evidence of their spread to all parts of the UK (REFS). We will exploit recent developments, such as confirmed ML-susceptible and ML-resistant isolates of P. ovis mites held in culture at Moredun as well as a chromosomal-level genome assembly for P. ovis. We then propose a multi-pronged approach of genetic crossing with bulk segregant analysis (BSA), transcriptomics, and comparative genomics to identify the mechanisms of resistance to the macrocyclic lactones in P. ovis mites, with population genomics to track the emergence and spread of resistance in the UK.
Short titleSheep Scab Resistance
StatusActive
Effective start/end date1/09/2431/08/27

Keywords

  • Scab
  • Sheep
  • Psoroptes ovis
  • Resistance
  • Evolution
  • Molecular
  • Macrocyclic lactones
  • Organophosphates
  • Genomics
  • Transcriptomics
  • RNAi
  • qPCR
  • Molecular Epidemiology

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