Repellent and feeding deterrent activity of a natural formulation from plant extracts on rabbit and human skin against Aedes aegypti

摘要

Aedes aegypti mosquito females transmit diseases such as Dengue, Yellow fever, Zika fever andChikungunya associated with mortality in many developing countries. Zika fever has neither treatmentnor vaccine. Personal protection by application of the skin repellents is the major control approach.Though synthetic skin repellents are effective, they are toxic however the natural mosquito repellentssuch as Ballet? are not effective. The purpose of the study was to develop a natural repellent formulationthat can provide 100% repellency. A formulation was developed from a combination of Azadirachtaindica, Eucalyptus citriodora, Ocimum basilicum and Chrysanthemum cinerariaefolium extracts. Theywere applied thinly on rabbit ears and tested with starved Aedes aegypti females. Observations weremade on the effect of the test combination, frequency of mosquito landing and blood engorgement. Thecombination that worked on rabbits was then tested on human skin of volunteers. The formulationprovided complete protection, had mosquito paralytic effect and had higher repellent activity thanBallet? (p<0.001). The final formulation that may scale up and applied for human use is a combinationof Azadirachta indica, Eucalyptus citriodora, Ocimum basilicum and Chrysanthemum cinerariaefoliumextracts.