Posted by Vector and Vector-borne Disease Committee
January 10, 2023
Tian,Y., et al. University of Florida. Email: yuexun1220@gmail.com
- Journal of Medical Entomology https://doi.org/10.1093/jme/tjac185
Abstract [condensed]:
Three Ripicephalus sanguineus s.l. (brown dog tick) strains, one from a laboratory colony (NC) and two from colonies originally collected from Florida (FL) and California (CA), were evaluated for resistance against permethrin and fipronil. Metabolic detoxification mechanisms were evaluated in the FL strain using three synergists, and a polymerase chain reaction assay was used to detect a resistance mutation in all strains. The NC strain was susceptible to both permethrin and fipronil, whereas both the FL and CA strains exhibited high resistance to permethrin and tolerance to fipronil. The synergist tests and PCR results indicated that the FL strain utilized both metabolic resistance and target site insensitivity against permethrin, whereas the CA strain was documented to have the target-site insensitivity resistant allele. Fipronil resistance was not detected suggesting this acaricide may provide suitable tick control.
Note: This study provides evidence of permethrin resistance in Rhipicephalus sanguineus ticks, including a colony originating from Imperial County, CA. Results indicated that fibronil would be a more effective treatment for these populations.