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: B Salafsky, K Ramaswamy, Y X He, G L Anderson, D K Nowicki, T Shibuya
• Journal: The American journal of tropical medicine and hygiene (Am J Trop Med Hyg) Vol. 58 Issue 6 Pg. 828-34 (Jun 1998) ISSN: 0002-9637 [Print] United States
• PMID: 9660474 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Insect Repellents
• DEET

Topics

• Administration, Topical
• Animals
• DEET (administration & dosage, pharmacology, therapeutic use)
• Disease Models, Animal
• Insect Repellents (administration & dosage, pharmacology, therapeutic use)
• Male
• Mice
• Microscopy, Electron
• Schistosoma mansoni (drug effects, physiology, ultrastructure)
• Schistosomiasis mansoni (prevention & control)
• Skin (parasitology)