Methods of testing and analyzing excito-repellency responses of malaria vectors to insecticides

A new test system that includes an excito-repellency test box, test procedures, and statistical treatment of data is described. The method consists of enclosing 25 mosquitoes in an exposure chamber lined with insecticide-treated or untreated (control) test papers. Each chamber has a single portal for mosquitoes to escape to a receiving cage, and numbers escaping are manually recorded at 1-min intervals. The exposure chamber accommodates a screened, 2nd chamber that, when placed in the exposure chamber, prevents the mosquitoes from making physical contact with test papers. A full assay utilized one exposure chamber that permits physical contact with insecticide-treated papers, one chamber that permits physical contact with control papers, one chamber that prevents physical contact with insecticide-treated papers, and a 4th chamber that prevents contact with control papers. After insecticide exposure, test populations are held for observations on 24-h mortalities. A survival analysis approach is described for estimating mosquito escape rates and for comparing differences in mosquito escape rates, with or without physical contact with insecticide, among populations, insecticides, and doses of insecticide.