A preliminary investigation into resistance to synthetic pyrethroids by the sheep biting louse (Bovicola ovis) in New Zealand

Authors: Wilson JA, Litchfield D, Heath ACG, Quilter S, Nottingham R, McKay C
Publication: New Zealand Veterinary Journal, Volume 45, Issue 1, pp 8-10, Feb 1997
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Animal remedies/veterinary medicines, Inflammation, Integument/skin/wool/hair/fur/feather, Disease/defect, Treatment/therapy, Pest/pesticides, Agricultural compounds, Parasites - external
Article class: Scientific Article

---

Abstract: Increasing reports of failure of synthetic pyrethroids for the control of Bovicola ovis on sheep lead to a preliminary investigation into the insecticide resistance status of this pest during 1994. Eighteen strains of lice from North and South Island flocks experiencing failure of synthetic pyrethroid treatments to control lice were exposed to cypermethrin (high-cis) in a treated surface (contact) bioassay. Lice from a group of “hermit” sheep were chosen as a reference susceptible strain against which resistance of field strains was measured and resistance factors (RFs) calculated. Low to moderate resistance to cypermethrin (high-cis) was demonstrated, with RFs ranging from 1.0 to 12.4.

---