Repellency screening of herbal products against the dengue fever vector, Aedes aegypti (Diptera: Culicidae)

Methods Plant products were evaluated for repellency in a mosquito cage containing 250 bloodstarved female Ae. aegypti under laboratory conditions, by using the human-bait technique from the standard World Health Organization (WHO) method. DEET also was tested as a standard synthetic repellent with a similar protocol to that for the plant samples. Approximately 0.1 ml of each test sample was applied evenly onto a 30 cm2 test site on one forearm of each human volunteer. Exposure experiments continued at 30 min intervals until at least two bites occurred in a threeminute period, or when a fi rst bite was followed by a confi rming bite (second bite) in the subsequent observation period. Each test was duplicated on different days for each of two human volunteers.