title: Evaluation of N,N-diethyl-m-toluamide (DEET) as a topical agent for preventing skin penetration by cercariae of Schistosoma mansoni.
abstract: The effect of skin application of N,N-diethyl-m-toluamide (DEET) on the penetration and migration behavior of cercariae of Schistosoma mansoni was evaluated in vitro and in vivo in a mouse model. These studies showed that DEET at concentrations of 7.5% or higher was 100% effective in immobilizing and killing cercariae of S. mansoni in vitro. Ultrastructural studies on such DEET-exposed cercariae showed transformative and degenerative changes involving both tegument and deeper parenchymal structures. Fatal tissue lesions were evident as early as 5 min postexposure to DEET, and became more extensive with increasing exposure time. Cutaneous application of DEET (as a pure chemical in isopropanol or as a commercial insect repellent preparation) was more than 99% effective in preventing entry of S. mansoni cercariae into the mouse tail skin. Radiolabeling and tracer studies confirmed that 7.5% DEET applied to the skin prior to infection was highly effective in preventing schistosomular migration to the lungs.
authors.affiliation: Department of Biomedical Sciences, College of Medicine, University of Illinois, Rockford 61107, USA.
authors.forename: B
authors.initials: B
authors.lastname: Salafsky
authors.forename: K
authors.initials: K
authors.lastname: Ramaswamy
authors.forename: Y X
authors.initials: YX
authors.lastname: He
authors.forename: G L
authors.initials: GL
authors.lastname: Anderson
authors.forename: D K
authors.initials: DK
authors.lastname: Nowicki
authors.forename: T
authors.initials: T
authors.lastname: Shibuya
mesh_terms: D000287:Administration, Topical; D000818:Animals; D003671:DEET / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D007302:Insect Repellents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D012550:Schistosoma mansoni / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D012555:Schistosomiasis mansoni / Q000517:prevention & control*; D012867:Skin / Q000469:parasitology
chemical_list: D007302:Insect Repellents; D003671:DEET