Background: Human head louse, De Geer, 1767 (Anoplura: Pediculidae), is one of the most frequent ectoparasites infesting worldwide. Reduced sensitivity to treatment due to genetic mutations, in particular knockdown resistance () (or target site insensitivity) allele, has led to this infestation prevalence. Molecular characterization of this resistance has a crucial impact on selecting appropriate treatment protocol. The aim of this study was to investigate kdr gene mutations on voltage-sensitive sodium channel (VSSC) among wild head lice samples from Fars province, southern Iran.
Methods: Head lice were collected using plastic detection combs on girls enrolled in public schools from 10 counties in Fars province. The specimens were screened in 10 pools (each pool per county containing 35 specimens), with three pools (30%) being positive. Following species identification with valid entomological keys, 350 (68%) out of 514 randomly collected adult head lice were analyzed after their somatic genomic DNA extraction using Sinaclon kit. Samples were investigated by polymerase chain reactions (PCR), and the amplicon was subsequently sequenced.
Results: Sequence analysis showed that the sodium channel genes in the pooled ectoparasites had two intron and three exon regions. Single (L840F), double (I836L, E837K), and triple novel point mutations (V875L, Q876P, S879V); the last involving two concomitant allelic substitutions; were discovered in the second and third exon regions of head louse DNA on chromosome II from three (30%) counties. Other exon or intron regions remained non-mutated from the remaining seven counties.
Conclusions: The detection of six amino acid substitutions from 30% of examined head lice among infested schoolgirls reveal that mutants are minutely developing. These findings provide further incentive to recapitulate the legitimacy of current control measures and resolve dynamics of resistance in human head louse populations.
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http://dx.doi.org/10.1016/j.parepi.2022.e00252 | DOI Listing |
Sci Rep
January 2025
Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
Head lice infestation remains one of the most common child problems. This problem is not only attributed to the ability of head lice to spread rapidly but also because of the head lice resistance that develops from incomplete or improper treatment. Pyrethroids are a group of medications that have been widely used for the treatment of head lice.
View Article and Find Full Text PDFPathogens
December 2024
Department of Medical Microbiology, Acibadem University School of Medicine, Istanbul 34752, Türkiye.
Head lice infestation (HLI), caused by De Geer, 1767, has long been a common global problem of school children. Permethrin is an old pyrethroid derivative that has been used commonly for its treatment, and it exerts its activity over the voltage-sensitive calcium channels (VSCC) of the lice. There has been a growing list of persistent HLI cases lately in the world among patients using permethrin, and knockdown resistance (kdr)-related point mutations on VSCC have been identified and reported from those resistant lice samples.
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