Survey of possible insecticide resistance in body lice.

WHO inaugurated in 1953 a global survey of the susceptibility of the body lice to insecticides. The test used consisted, essentially, of treating a balbriggan type of cloth with dusting powder, placing the lice upon it, and assessing the mortality 24 hours later. The present paper describes the results of tests carried out in 37 countries. A significant resistance to DDT has been found to be present in many countries, and there are indications of several instances of BHC-resistance.