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

PICOLLO MI; DAVID L. REED; A. C. TOLOZA; M ASCUNCE

Orlando, FL

Congreso; XXV international congress of entomology; 2016

The human head lice, Pediculus humanus capitis, have been associated with us since the beginningof humankind, probably since our pre-hominid African ancestors. Every yearmillions of children in both developed and developing countries are infected byhead lice. To control them, products containing pyrethroids are beingintensively used leading to the development of insecticide resistant among lousepopulations worldwide. Pyrethroids act on the nervous system affectingvoltage-sensitive sodium channels (VSSC). Three point mutations at thecorresponding amino acid sequence positions M815I, T917I and L920F in the voltage-gatedsodium channel gene are responsible for contributing to the knockdownresistance (kdr). Despite its medicalimportance, little is known about the movement patterns and the effects ofinsecticide treatments on the genetic structure of the insect populations. Inthis study, we assess the effects of evolutionary processes such as migrationand genetic drift on the evolution of resistance among head louse populationsfrom Argentina. To that end, we use 15 microsatellite loci and kdr alleles couple with toxicologicalphenotypes (resistance, sensitive). Toxicological studies revealed that theresistant factor (RF) to pyrethroids varied from 30 to 80. Pyrethroidresistance alleles (kdr) were foundin an overall frequency of 88%. Most of the populations departure fromHardy-Weinberg expectations. We used both multivariate and model-based Bayesianclustering approaches. Knowing the processes that shape the genetic structureof parasite populations is critical to understand how insecticide resistanceevolves and for the design of effective control methods.http://entsoc.org/membership/ice-early-bird-extended-esa-members