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Conference proceedings
Konferenzposter
Monographie
Konferenzposter
Monographie
Date
2018
DOI
Prevalence of kdr-genotype of German headlice and relevance for pediculosis treatment
Prevalence of kdr-genotype of German headlice and relevance for pediculosis treatment
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Containing Item
28th Annual Meeting of the German Society for Parasitology (28. : 2018 : Berlin)
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Citation
Prevalence of kdr-genotype of German headlice and relevance for pediculosis treatment, 2018. [online]. Berlin. Verfügbar unter: https://openumwelt.de/handle/123456789/5533
Abstract english
Introduction: Infestations with Pediculus humanus var. capitis are a relevant Public Health issue. Treatment efficacy seems decreasing and emergence of resistant lice in particular to pyrethroids is a suspected reason. Non-synonymous mutations in the gene encoding the a-subunit of a voltage gated sodium channel (VSSC), so-called knock-down resistance (kdr) mutations, are implicated in pyrethroid resistance in insects. The kdr-genotype was previously described to occur in ~9 of 10 headlice from Germany but was found not to correlate with failure of a pyrethroid-containing pediculocide in a sponsored-study setting. Objectives: Determine current kdr-mutation frequency and population structure of headlice in Germany and relate this to treatment outcome of pediculocides used by patients. Material & Methods: Questionnaires on patient demographics, on chosen therapy and success as well as louse sampling sets were distributed via local health authorities. Study participants were invited to send back questionnaires and headlice or nits. Samples and questionnaires obtained were evaluated using STATA software and DNA amplicon analyses, respectively. Kdr and PM2 and S2 intergenic region genotyping was performed using published protocols and sequences analysed using Geneious software. Results: Headlice were obtained from 206 patients and, where possible, 2 individual headlice/eggcontaining or empty nits per patient were processed. In total 167 headlice could be genotyped. All except one were homozygous for kdr. For PM2 sequences, 10 genotypes were observed with 119 of 130 samples belonging to genotype EU928850. Only two S2 genotypes were observed with one being represented by a single sample. Questionnaire data of 135 cases indicated that pyrethroid-based pediculocides are used in roughly 4 of 10 cases with treatment success comparable to that of nonpyrethroid-based, UBA-listed pediculocides. Conclusion: Prevalence of the kdr-genotype of headlice currently approaches 100%. The mutations are found in genetically distinct fractions of the parasite population. Observational findings agree with previous data that the kdr-mutation is unlikely a major cause of treatment failure. In: 28th Annual Meeting of the German Society for Parasitology : Programme. Berlin: Freie Universität, 2018, S. 226-227. URL: https://www.parasitology-meeting.de/fileadmin/congress/media/dgp2018/druckelemente/DGP2018_Programme.pdf