Population genetic analysis in human head lice: comparison between microsatellite and insecticide resistance markers

ASCUNCE MARINA; A. C. TOLOZA; DAVID REED

Conferencia; International Conference on Phthiraptera 6; 2018

Every year millions of children in bothdeveloped and developing countries are infected by head lice. To control them,products containing pyrethroids are being intensively used leading to thedevelopment of insecticide resistant among louse populations worldwide.Pyrethroids act on the nervous system affecting voltage-sensitive sodiumchannels (VSSC). Three point mutations at the corresponding amino acid sequencepositions M815I, T917I and L920F in the voltage-gated sodium channel gene areresponsible for contributing to the knockdown resistance (kdr). Despite itsmedical importance, little is known about the movement patterns and the effectsof insecticide treatments on the genetic structure of the insect populations.In this study, we assess the effects of evolutionary processes such asmigration and genetic drift on the evolution of resistance among head lousepopulations from Argentina. To that end, we use 15 microsatellite loci and kdralleles couple with toxicological phenotypes (resistance, sensitive).Toxicological studies revealed that the resistant factor (RF) to pyrethroidsvaried from 30 to 80. Pyrethroid resistance alleles (kdr) were found in an overall frequency of 88%. Most of thepopulations departure from Hardy-Weinberg expectations. We used bothmultivariate and model-based Bayesian clustering approaches. Knowing theprocesses that shape the genetic structure of parasite populations is criticalto understand how insecticide resistance evolves and for the design ofeffective control methods.