Human lice: Past, present and future control

Human lice represent one of the longest ectoparasitic relationships associated with mankind. Whereas the body louse vectors bacterial diseases that have killed millions, the head louse does not but represents an economic and social concern worldwide. A crisis exists in the control of lice due to the availability of only a few new pediculicides and the occurrence of resistance. In this review, we summarize data that validates the knockdown resistance mechanism (kdr) as the main cause of control failures to the pyrethrin/pyrethroid-based pediculicides and the molecular diagnostics used to determine kdr worldwide. New commercially-available pediculicide are discussed in terms of their use in sustainable resistance management approaches. Lastly, the optimization of dose, the timing of exposure, and the assessment of transcript levels during tolerance is used to identify detoxification genes that metabolize ivermectin as a proof of principle experiment, indicating that such an approach may allow proactive resistance management.