HEAD LICE-HOST INTERACTION: HUMAN SCALP EXTRACTS MODIFY THE BEHAVIOUR OF PEDICULUS HUMANUS CAPITIS.

PAOLA GONZALEZ-AUDINO; FEDERICO GALASSI; ISABEL ORTEGA INSAURRALDE; ARIEL CEFERINO TOLOZA; MARIA INES PICOLLO

Congreso; 1st Joint meeting ISCE/ALAEC; 2016

International Society of chemical ecology

P. h. capitis is a cosmopolitan ectoparasite that affects the head of their human hosts. It ispresent in children of school age, in both developed and developing countries. It is beenalready stablished that P.h. capitis prefer to infest some individulas above others.However, no studies have gained insight into the reasons behind the existence ofsusceptible and non-susceptible individuals. The main mechanism by which lousetransmision occurs is the direct host to host contact.Behavioural assays were performedin order to study environmental factors that affect locomotor activity and to evaluate ifhuman scalp extracts modify the behaviour of head lice. Extracts were collected byrubbing filter paper onto scalp surface. Data were processed with video tracking systemEthoVision XT 10.1. VOCs present in the human scalp extracts were collected andanalysed by Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry(SPME-CG-MS).In a circular arena, headlice increase their locomotor activiy at 30°Cand dark conditions and are arrested by the extracts collected from human scalp.Inolfactometer, head lice were significantly attracted to volatiles from the human source.The chemical composition of the extracts showed the presence of hydrocarbons, alcohols,diols, saturated and unsaturated ketones, aldehydes and fatty and short chain acids. Therole of these compounds alone and in mixtures is currently under study. These resultsrepresent the basis for the study of chemical cues involved in human susceptibility tohead lice.Ortega Insaurralde et al., J. Med. Entomol. 2015.