The efficacy of a repellent formulation can also be evaluated in repellent room tests with free-flying mosquitoes under more realistic yet standardized conditions. This method is an in-house development by the mosquito specialists from Biogents.
50 host-seeking mosquito females are released into a 30 m³ climatized test room. The test formulation is applied to the forearms of the volunteers, and efficacy is evaluated shortly after. During tests, only the treated skin is exposed while the rest of the body is protected from bites by standardized clothing. The volunteer enters the room and documents the number of landings and bites on the treated skin during a testing time of ten minutes. Afterwards, the next volunteer enters the room for ten minutes. The biting activity of the test mosquitoes is verified with the other untreated arm – at least by one volunteer once every hour.
The efficacy of a test formulation is usually compared to a reference formulation, and evaluated according to the following criteria: protection time until first bite and until two to three bites occur on the treated skin (= break-off). Repellent room tests are performed with five volunteers and two mosquito species (usually of the genera Aedes and Culex). The Biogents Contract R & D team takes special precautions that the vectors do not transmit diseases.