Evaluating repellence properties of a catnip essential oil-based mosquito repellent using the human landing catch method in Eastern Uganda

Abstract

Mosquitoes (Diperta: Culidae) act as vectors for several diseases, including malaria, dengue fever and yellow fever. Mosquito repellents represent one of the primary measures used to reduce the risk of these diseases in humans by reducing mosquito landing and biting events. Nepetalactone, a natural insect repellent primarily found in the essential oil of catnip (Lamiaceae; Nepeta cataria), has established mosquito repellence properties, but has not been widely exploited as a mosquito repellent in malaria-endemic regions such as Sub-Saharan Africa. Here, we evaluated the potential of a locally produced lotion containing catnip essential oil (comprising > 92% nepetalactone) for use as a mosquito repellent in Eastern Uganda. Using the human landing catch method in field trials, we analysed the effectiveness of a lotion containing 2% or 6% catnip oil at repelling mosquitoes compared to a lotion lacking catnip essential oil as a negative control and to a commercial repellent containing 15% DEET as a positive control. We found that lotions containing both concentrations of catnip essential oil were highly effective at preventing mosquito landing, with 6% catnip oil performing as well as 15% DEET. Our findings suggest that nepetalactone could be used as a natural, locally sourced and effective alternative to synthetic commercial mosquito repellents, thereby representing a viable import substitution option for protection against mosquito-borne diseases.