Knockdown resistance allele frequencies in North American head louse (Anoplura: Pediculidae) populations.

TitleKnockdown resistance allele frequencies in North American head louse (Anoplura: Pediculidae) populations.
Publication TypeJournal Article
Year of Publication2014
AuthorsYoon, KSup, Previte, DJ, Hodgdon, HE, Poole, BC, Kwon, DHo, El-Ghar, GEAbo, Lee, SHyeock, J Clark, M
JournalJ Med Entomol
Volume51
Issue2
Pagination450-7
Date Published2014 Mar
ISSN0022-2585
KeywordsAnimals, Canada, Gene Frequency, Genotyping Techniques, Insecticide Resistance, Insecticides, Mutation, Pediculus, Permethrin, Sodium Channels, United States
Abstract

The study examines the extent and frequency of a knockdown-type resistance allele (kdr type) in North American populations of human head lice. Lice were collected from 32 locations in Canada and the United States. DNA was extracted from individual lice and used to determine their zygosity using the serial invasive signal amplification technique to detect the kdr-type T917I (TI) mutation, which is most responsible for nerve insensitivity that results in the kdr phenotype and permethrin resistance. Previously sampled sites were resampled to determine if the frequency of the TI mutation was changing. The TI frequency was also reevaluated using a quantitative sequencing method on pooled DNA samples from selected sites to validate this population genotyping method. Genotyping substantiated that TI occurs at high levels in North American lice (88.4%). Overall, the TI frequency in U.S. lice was 84.4% from 1999 to 2009, increased to 99.6% from 2007 to 2009, and was 97.1% in Canadian lice in 2008. Genotyping results using the serial invasive signal amplification reaction (99.54%) and quantitative sequencing (99.45%) techniques were highly correlated. Thus, the frequencies of TI in North American head louse populations were found to be uniformly high, which may be due to the high selection pressure from the intensive and widespread use of the pyrethrins- or pyrethroid-based pediculicides over many years, and is likely a main cause of increased pediculosis and failure of pyrethrins- or permethrin-based products in Canada and the United States. Alternative approaches to treatment of head lice infestations are critically needed.

DOI10.1603/me13139
Alternate JournalJ Med Entomol
PubMed ID24724296
PubMed Central IDPMC4007213
Grant ListR01 AI045062 / AI / NIAID NIH HHS / United States
R56 AI081933 / AI / NIAID NIH HHS / United States
R01 AI045062-04A3 / AI / NIAID NIH HHS / United States