title: High-resolution melt analysis for the detection of a mutation associated with permethrin resistance in a population of scabies mites.
abstract: Permethrin as a topical acaricide cream is widely used to treat scabies. The neuronal voltage-sensitive sodium channel (Vssc), necessary for the generation of action potentials in excitable cells, is the target of pyrethroid acaricides such as permethrin. Pyrethroid resistance has been linked to specific mutations in the Vssc gene. Following the partial sequencing of the Vssc gene in the scabies mite Sarcoptes scabiei (L.) (Astigmata: Sarcoptidae), we compared Vssc gene sequences from permethrin-sensitive and -tolerant S. scabiei var. canis Gerlach mites, and identified a G to A single nucleotide polymorphism (SNP) in permethrin-tolerant mites resulting in an amino acid change from glycine to aspartic acid in domain III S6. The mutation is in a region of the gene where mutations have been identified in a range of pyrethroid-resistant arthropods. Results of in vitro permethrin exposure assays showed that survival rates for mites bearing the mutation were similar to those previously reported for mites from human subjects where clinical tolerance to permethrin had been observed. A real-time polymerase chain reaction-high-resolution melt (PCR-HRM) assay was developed to detect this SNP. This assay provides a useful methodology for screening for this and other mutations associated with permethrin resistance in scabies mite populations and thus facilitates surveillance for acaricide resistance.
authors.affiliation: Clinton Tropical Laboratory, Queensland Institute of Medical Research and Australian Centre for International and Tropical Health and Nutrition, University of Queensland, Brisbane, Queensland, Australia. Cielo.Pasay@qimr.edu.au
authors.forename: C
authors.initials: C
authors.lastname: Pasay
authors.forename: L
authors.initials: L
authors.lastname: Arlian
authors.forename: M
authors.initials: M
authors.lastname: Morgan
authors.forename: D
authors.initials: D
authors.lastname: Vyszenski-Moher
authors.forename: A
authors.initials: A
authors.lastname: Rose
authors.forename: D
authors.initials: D
authors.lastname: Holt
authors.forename: S
authors.initials: S
authors.lastname: Walton
authors.forename: J
authors.initials: J
authors.lastname: McCarthy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D007305:Insecticide Resistance / Q000235:genetics; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D026023:Permethrin / Q000494:pharmacology*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D020641:Polymorphism, Single Nucleotide; D012520:Sarcoptes scabiei / Q000187:drug effects*; D012532:Scabies / Q000188:drug therapy; D015222:Sodium Channels / Q000235:genetics*; D013997:Time Factors
chemical_list: D007306:Insecticides; D015222:Sodium Channels; D026023:Permethrin