GEPHE SUMMARY Print
Gephebase Gene
Entry Status
Published
GepheID
GP00000846
Main curator
Martin
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Pediculus capitis
Trait State in Taxon B
Pediculus capitis - resistant
Ancestral State
Taxon A
Taxonomic Status
Taxon A
Common Name
human louse
Synonyms
human louse; body lice; head lice; human lice; Pediculus humanus Linnaeus, 1758
Rank
species
Lineage
Show more ... Protostomia; Ecdysozoa; Panarthropoda; Arthropoda; Mandibulata; Pancrustacea; Hexapoda; Insecta; Dicondylia; Pterygota; Neoptera; Paraneoptera; Psocodea; Phthiraptera; Anoplura; Pediculidae; Pediculus
NCBI Taxonomy ID
is Taxon A an Infraspecies?
No
Taxon B
Common Name
human louse
Synonyms
human louse; body lice; head lice; human lice; Pediculus humanus Linnaeus, 1758
Rank
species
Lineage
Show more ... Protostomia; Ecdysozoa; Panarthropoda; Arthropoda; Mandibulata; Pancrustacea; Hexapoda; Insecta; Dicondylia; Pterygota; Neoptera; Paraneoptera; Psocodea; Phthiraptera; Anoplura; Pediculidae; Pediculus
NCBI Taxonomy ID
is Taxon B an Infraspecies?
No
GENOTYPIC CHANGE
Mutation #1
Presumptive Null
No
Molecular Type
Aberration Type
SNP
SNP Coding Change
Nonsynonymous
Molecular Details of the Mutation
M815I = M827I
Experimental Evidence
Taxon A Taxon B Position
Codon - - -
Amino-acid - - -
Authors
Hodgdon HE; Yoon KS; Previte DJ; Kim HJ; Aboelghar GE; Lee SH; Clark JM
Abstract
Pediculosis is the most prevalent parasitic infestation of humans. Resistance to pyrethrin- and pyrethroid-based pediculicides is due to knockdown (kdr)-type point mutations in the voltage-sensitive sodium channel alpha-subunit gene. Early detection of resistance is crucial for the selection of effective management strategies.

Kdr allele frequencies of lice from 14 countries were determined using the serial invasive signal amplification reaction. Lice collected from Uruguay, the United Kingdom and Australia had kdr allele frequencies of 100%, while lice from Ecuador, Papua New Guinea, South Korea and Thailand had kdr allele frequencies of 0%. The remaining seven countries investigated, including seven US populations, two Argentinian populations and populations from Brazil, Denmark, Czech Republic, Egypt and Israel, displayed variable kdr allele frequencies, ranging from 11 to 97%.

The newly developed and validated SISAR method is suitable for accurate monitoring of kdr allele frequencies in head lice. Proactive management is needed where kdr-type resistance is not yet saturated. Based on sodium channel insensitivity and its occurrence in louse populations resistant to pyrethrin- and pyrethroid-based pediculicides, the T917I mutation appears to be a key marker for resistance. Results from the Egyptian population, however, indicate that phenotypic resistance of lice with single or double mutations (M815I and/or L920F) should also be determined.

(c) 2010 Society of Chemical Industry.
Mutation #2
Presumptive Null
No
Molecular Type
Aberration Type
SNP
SNP Coding Change
Nonsynonymous
Molecular Details of the Mutation
T929I (ACC to ATC or ATA) = L932F
Experimental Evidence
Taxon A Taxon B Position
Codon - - -
Amino-acid - - -
Authors
Vais H; Williamson MS; Devonshire AL; Usherwood PN
Abstract
Recent progress in the cloning of alpha (para) and beta (TipE) Na channel sub-units from Drosophila melanogaster (fruit fly) and Musca domestica (housefly) have facilitated functional expression studies of insect Na channels in Xenopus laevis oocytes, assayed by voltage clamp techniques. The effects of Type I and Type III pyrethroids on the biophysical properties of these channels are critically reviewed. Pyrethroid resistance mutations (termed kdr and super-kdr) that reduce the sensitivity of the insect Na channel to pyrethroids have been identified in a range of insect species. Some of these mutations (e.g. L1014F, M918T and T929I) have been incorporated into the para Na channel of Drosophila, either individually or in combination, to investigate their effects on the sensitivity of this channel to pyrethroids. The kdr mutation (L1014F) shifts the voltage dependence of both activation and steady-state inactivation by approximately 5 mV towards more positive potentials and facilitates Na channel inactivation. Incorporation of the super-kdr mutation (M918T) into the Drosophila Na channel also increases channel inactivation and causes a > 100-fold reduction in deltamethrin sensitivity. These effects are shared by T929I, an alternative mutation that confers super-kdr-like resistance. Parallel studies have been undertaken using the rat IIA Na channel to investigate the molecular basis for the low sensitivity of mammalian brain Na channels to pyrethroids. Rat IIA channels containing the mutation L1014F exhibit a shift in their mid-point potential for Na activation, but their overall sensitivity to permethrin remains similar to that of the wild-type rat channel (i.e. both are 1000-fold less sensitive than the wild-type insect channel). Mammalian neuronal Na channels have an isoleucine rather than a methionine at the position (874) corresponding to the super-kdr (M918) residue of the insect channel. Replacement of the isoleucine of the wild-type rat IIA Na channel with a methionine (I874M) increases deltamethrin sensitivity 100-fold. In this way, studies of wild-type and mutant Na channels of insects and mammals are providing a molecular understanding of kdr and super-kdr resistance in insects, and of the low pyrethroid sensitivity of most mammalian Na channels. They are also giving valuable insights into the binding sites for pyrethroids on these channels.
Mutation #3
Presumptive Null
No
Molecular Type
Aberration Type
SNP
SNP Coding Change
Nonsynonymous
Molecular Details of the Mutation
L920F
Experimental Evidence
Taxon A Taxon B Position
Codon - - -
Amino-acid - - -
Authors
Hodgdon HE; Yoon KS; Previte DJ; Kim HJ; Aboelghar GE; Lee SH; Clark JM
Abstract
Pediculosis is the most prevalent parasitic infestation of humans. Resistance to pyrethrin- and pyrethroid-based pediculicides is due to knockdown (kdr)-type point mutations in the voltage-sensitive sodium channel alpha-subunit gene. Early detection of resistance is crucial for the selection of effective management strategies.

Kdr allele frequencies of lice from 14 countries were determined using the serial invasive signal amplification reaction. Lice collected from Uruguay, the United Kingdom and Australia had kdr allele frequencies of 100%, while lice from Ecuador, Papua New Guinea, South Korea and Thailand had kdr allele frequencies of 0%. The remaining seven countries investigated, including seven US populations, two Argentinian populations and populations from Brazil, Denmark, Czech Republic, Egypt and Israel, displayed variable kdr allele frequencies, ranging from 11 to 97%.

The newly developed and validated SISAR method is suitable for accurate monitoring of kdr allele frequencies in head lice. Proactive management is needed where kdr-type resistance is not yet saturated. Based on sodium channel insensitivity and its occurrence in louse populations resistant to pyrethrin- and pyrethroid-based pediculicides, the T917I mutation appears to be a key marker for resistance. Results from the Egyptian population, however, indicate that phenotypic resistance of lice with single or double mutations (M815I and/or L920F) should also be determined.

(c) 2010 Society of Chemical Industry.
RELATED GEPHE
Related Genes
No matches found.
Related Haplotypes
1
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