A comparison of botanical and synthetic substances commonly used to prevent head lice (Pediculus humanus var. capitis) infestation.
BACKGROUND
Pediculosis, caused by head lice (Pediculidae: Pediculus humanus var. capitis), is experiencing a global resurgence, with the prevalence in primary schools averaging as high as 40% in some areas regardless of socioeconomic factors. Control efforts using chemical treatments are becoming increasingly ineffective, with insecticide resistance recorded in several countries. Prevention using repellents and oils would be useful if they limited transmission. Many commercially available substances reputedly have effective repellent qualities, but remain untested.


METHODS
This study tested the preventative efficacy of N,N-diethyl-3-methylbenzamide (DEET) against several commercially available botanicals to clarify their value as transmission inhibitors, irritants, repellents, and antifeedants.


RESULTS
The transfer of head lice to treated hairs was limited by the slippery nature of the oils rather than their repellent qualities. Irritancy was not important because lice proceeded despite being highly irritated, except in the case of coconut. Tea tree and peppermint caused the most repellence, and tea tree and lavender prevented some blood feeding on treated skin. Comparatively, tea tree oil was most efficacious, with DEET ranking equal second overall with coconut, peppermint, and a botanical mixture.


CONCLUSIONS
Neither DEET nor any of the botanicals tested showed sufficient preventative efficacy to be endorsed.
Canyon
Deon V
DV
School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville, Qld, Australia. Deon.Canyon@jcu.edu.au
Speare
Rick
R
D000279:Administration, Cutaneous; D000818:Animals; D003671:DEET / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D018562:Disease Transmission, Infectious / Q000517:prevention & control; D006203:Hair Preparations; D006801:Humans; D010373:Lice Infestations / Q000473:pathology / Q000517:prevention & control* / Q000635:transmission; D010374:Pediculus / Q000187:drug effects; D008517:Phytotherapy; D010938:Plant Oils / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D010946:Plants, Medicinal; D012536:Scalp Dermatoses / Q000473:pathology / Q000517:prevention & control
D006203:Hair Preparations; D010938:Plant Oils; D003671:DEET