Expansion of the Knockdown Resistance Frequency Map for Human Head Lice (Phthiraptera: Pediculidae) in the United States Using Quantitative Sequencing
Authors
Gellatly, Kyle J.Krim, Sarah
Palenchar, Daniel J.
Shepherd, Katie
Yoon, Kyong Sup
Rhodes, Christopher J.
Lee, Si Hyeock
Marshall Clark, J.
UMass Chan Affiliations
Graduate School of Biomedical SciencesDocument Type
Journal ArticlePublication Date
2016-03-31Keywords
Pediculus humanus capitishuman head louse
knockdown resistance frequency
quantitative sequencing
Computational Biology
Entomology
Genetics
Parasitic Diseases
Skin and Connective Tissue Diseases
Metadata
Show full item recordAbstract
Pediculosis is a prevalent parasitic infestation of humans, which is increasing due, in part, to the selection of lice resistant to either the pyrethrins or pyrethroid insecticides by the knockdown resistance (kdr) mechanism. To determine the extent and magnitude of thekdr-type mutations responsible for this resistance, lice were collected from 138 collection sites in 48 U.S. states from 22 July 2013 to 11 May 2015 and analyzed by quantitative sequencing. Previously published data were used for comparisons of the changes in the frequency of thekdr-type mutations over time. Mean percent resistance allele frequency (mean % RAF) values across the three mutation loci were determined from each collection site. The overall mean % RAF (+/-SD) for all analyzed lice was 98.3 +/- 10%. 132/138 sites (95.6%) had a mean % RAF of 100%, five sites (3.7%) had intermediate values, and only a single site had no mutations (0.0%). Forty-two states (88%) had a mean % RAF of 100%. The frequencies ofkdr-type mutations did not differ regardless of the human population size that the lice were collected from, indicating a uniformly high level of resistant alleles. The loss of efficacy of the Nix formulation (Prestige Brand, Tarrytown, NY) from 1998 to 2013 was correlated to the increase inkdr-type mutations. These data provide a plausible reason for the decrease in the effectiveness of permethrin in the Nix formulation, which is the parallel increase ofkdr-type mutations in lice over time.Source
J Med Entomol. 2016 Mar 31. pii: tjw023. Link to article on publisher's siteDOI
10.1093/jme/tjw023Permanent Link to this Item
http://hdl.handle.net/20.500.14038/40072PubMed ID
27032417Related Resources
Link to Article in PubMedDistribution License
http://creativecommons.org/licenses/by-nc-nd/4.0/ae974a485f413a2113503eed53cd6c53
10.1093/jme/tjw023
Scopus Count
Except where otherwise noted, this item's license is described as http://creativecommons.org/licenses/by-nc-nd/4.0/