Findings on salmon louse resistance

Three of the partners in SLRC, PatoGen Analyse AS, NVH and UiB,  have today published results regarding novel methods for detection of single nucleotide polymorphisms associated with resistance towards pyrethroids and organophosphates in salmon louse. Results show that Real-Time PCR-analyses developed towards the genetic markers correlate very well with resistance properties of salmon lice.

Researcher Per Gunnar Espedal and Professor Frank Nilsen at the University of Bergen have identified genetic markers that can be used to differentiate between pyrethroid -resistant and -sensitive salmon lice. Numerous crossing experiments and analyzes of laboratory strains of lice with known resistance characteristics have been made, and historical material from more than 180 sea lice strains are reviewed to find candidates for PatoGen to continue working with.

Researcher Kiranpreet Kaur and Prof. Tor Einar Horsberg at the Norwegian School of Veterinary Science have identified genetic markers that can be used to differentiate between organophosphate -resistant and -sensitive salmon lice. The researchers have worked with laboratory strains with known resistance properties and used bioassay, biochemical analyzes and small-scale treatment trials, in combination with sequencing.  The work has benefited greatly from the salmon lice genome that is given access to through Sea Lice Research Centre.

PatoGen Analyse AS has developed Real-Time PCR-analyses that have been validated and tested on a selection of laboratory and field strains. The Real-Time PCR-analyses differentiates between the genetic variants identified by genome sequencing, and correlate with results from bioassays regarding sensitivity to the relevant insecticide.

 The researchers are now working to prepare scientific publications related both to the identification of markers, and analyzes PatoGen has performed in connection with the validation of these analyzes.

Efficient and sensitive methods for diagnosing resistance are crucial in order to manage and control drug resistance. Early detection of reduced sensitivity to a chemical can enable effective countermeasures to be enforced at a time point when these have a greater probability of being effective. Therefore, accurate and speedy identification of resistant L. salmonis is crucial. Detection of resistance prior to treatment, and the use of such analyses after treatment to evaluate treatment efficacy constitutes an important determinant for the integrated pest management (IPM) in the aquaculture industry.

 Patents have been filed for all novel aspects of this research.

Read more in the PatoGen magazine Pathos

13 August 2013