Mosquitoes, malaria and essential oils

Biocidal (insect repellent) preparations used against mosquito bites to prevent infection are reviewed, comparing the use of essential oils and natural aromatic materials with various synthetic topical agents. A synopsis of malaria prevention strategies and insecticidal toxicity is also discussed, in the light of emergent mosquito resistance to synthetic chemical pesticides.

The use of natural products for use as anti-malarials is also reviewed, finding that a serious divide occurs between a purely open approach, and the approach via the commercial interests of pharmaceutical and chemical companies. The latter tend to focus on the exploitation of single active chemicals, whilst the activity of whole botanical extracts is overlooked despite the fact that insect resistance to single actives is common; and resistance to whole plant extracts is rare. The European Union’s role in this issue is also discussed.

Better formulation technology is needed for topical repellents by providing more effective fixation for the essential oil content and incorporating strategies for controlled release of essential oil vapours, whilst providing solutions for the problem of potential dermal irritancy.