Chemical Communication of the Head Lice with the Human Host

Abstract

Purpose of Review: Transmission of head lice occurs primarily by direct host-to-host contact and via inanimate objects, called fomites. As for other hematophagous insects, chemical cues are likely involved in host detection, at least in the close range for the case of head lice. Recent Findings: The revision of the literature on the effect of chemical cues from the host on head lice behavior showed that volatiles in a combination but also individually from the human scalp trigger an attraction response on head lice. Studies also show that both infested and non-infested individuals have similar chemical profiles and that lice show no preference for volatiles from either group. Concerning the odors from different body parts, volatiles from scalp, arm, and foot produced similar attraction to lice when compared to volatiles from the scalp. However, complete extracts from different parts of the body (scalp, arm, and foot), lice seem to show a clear preference towards samples from the scalp over samples from the arm or foot. Summary: There is strong evidence of chemical communication between the head louse and its human host. Understanding the biochemical communication between head lice and the human host is essential not only to understanding the biological mechanisms of transmission but also to develop new tools for head lice control.