Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 2002; 7: 90–1
The biting activity of Culicoides spp biting midges in Scotland can interfere with a variety of outdoor activities during the summer. A recent survey indicated that 48% of visitors to Scotland during the summer would consider not returning at the same time of the year again because of biting midge activity. The objective of the study was to evaluate neem oil as a safe natural alternative to DEET (N,N-diethyl-m-toluamide)-based repellents.
In the first stage of the work, the response of midge antennae to a range of concentrations of neem oil was determined by electrophysiology studies. Behavioural assays were then conducted to determine the ‘distance’ repellence and antifeedant properties of neem oil. The result of the electrophysiology and behavioural studies were used to develop a prototype repellent formulation. This formulation was evaluated on volunteers using caged midges.
Electrophysiology studies indicated that midges could detect neem oil at concentrations as low as 0.01%. In behavioural tests, a significant reduction in midge feeding was observed at 0.01% neem oil, while at 1% biting was inhibited completely. A 1% solution also showed significant ‘distance’ repellence. A prototype insect repellent formulation containing 2% neem oil was developed and evaluated in cage-tests. The formulation was then refined to improve its distance repellence and re-evaluated using behavioural assays.
Cold-pressed neem oil was found to be effective in repelling midges and inhibiting biting. In the UK, it offers a safe alternative to DEET-based repellents for Culicoides spp biting midges. Neem may also offer protection against disease vectors such as mosquitoes.
