A new ivermectin formulation topically kills permethrin-resistant human head lice (Anoplura: Pediculidae).

TitleA new ivermectin formulation topically kills permethrin-resistant human head lice (Anoplura: Pediculidae).
Publication TypeJournal Article
Year of Publication2008
AuthorsStrycharz JP, Yoon KS, Clark MJ
JournalJournal of medical entomology
Volume45
Issue1
Pagination75-81
Date Published2008 Jan
AbstractThis study examines the effectiveness of a new ivermectin formulation for the topical treatment of the human head louse, Pediculus humanus capitis De Geer (Anoplura: Pediculidae). Permethrin-resistant lice originally obtained from south Florida and maintained on an in vitro rearing system were 100% susceptible to ivermectin formulations by using a semiclinical hair tuft bioassay. The formulation was 100% effective at killing lice using 1, 0.5, and 0.25% ivermectin concentrations after 10-min exposures. As judged by the lethal time (LT)50 and LT95 values, 0.5% formulated ivermectin was 3.8 and 3.2 times faster at killing lice, respectively, than 0.5% nonformulated ivermectin, indicating that the formulation may facilitate the penetration of ivermectin into the louse. The hair tuft-based bioassay in conjunction with the in vitro rearing system provides a standardized method to assess the comparative efficacy of pediculicide formulations in a reproducible format that mimics the exposure scenario that occurs on the human scalp.
Alternate JournalJ. Med. Entomol.