1907-1964 2012h-149 20thcentury american carson control ddt eastasia effectofhumanbeingson environmentalaspects environmentalexposure environmentalhealth environmentalism globalhealth history insectcontrol insectpests malaria medicalassistance nature neglecteddiseases pesticides poisoning prevention publichealth rachel unitedstates wa11aa1 wa240b369d1973 wa240h513e1971