01987nas a2200169   4500008004100000245013500041210006900176260000900245300001400254490000700268520143800275653000901713653001401722100002101736700002001757856004001777       2007                        eng d00aA comparison of botanical and synthetic substances commonly used to prevent head lice (Pediculus humanus var. capitis) infestation0 acomparison of botanical and synthetic substances commonly used t  c2007  a422 - 4260 v463 aBackground 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.10aDEET10arepellent1 aCanyon, Deon, V.1 aSpeare, Richard  uhttps://cats.myspecies.info/node/2001802nas a2200157   4500008004100000245008000041210006900121260000900190300001400199490000700213520130800220100002001528700002101548700001901569856005601588       2006                        eng d00aQuantification of blood intake of the head louse: Pediculus humanus capitis0 aQuantification of blood intake of the head louse Pediculus human  c2006  a543 - 5460 v453 aAlthough head lice, Pediculus humanus capitis, are globally prevalent blood-sucking ectoparasites, the amount of blood imbibed by head lice has not been determined. This study investigated this parameter, as regular loss of a small quantity of blood may lead to an iron deficiency and anaemia. Adult female lice (66), adult males (46), and nymphs (152) were weighed before and after feeding in groups of 17-109 lice. The average amounts of blood imbibed at a single feed were: adult female louse (0.0001579 ml), adult male (0.0000657 ml) and nymph (0.0000387 ml). Assuming three feeds per day by an average infection of 30 lice (10 females, 10 males, and 10 nymphs), the average child with active pediculosis would loose 0.008 ml of blood per day. This amount of blood loss is of no clinical significance even in iron-deficient children. The most heavily infected child observed with 2657 lice could be expected to loose 0.7 ml/day or 20.8 ml/month, which may be of clinical importance in a child on an adequate diet, and would be significant in an iron-deficient child. However, if head lice feed more often than three times a day, a heavy infestation would have a greater potential to lead to iron deficiency. The frequency of feeding of head lice on the head of the human host needs to be determined.1 aSpeare, Richard1 aCanyon, Deon, V.1 aMelrose, Wayne  uhttp://www.phthiraptera.info/Publications/46290.pdf