This episode covers the 1948 Nobel Prize in Physiology or Medicine, which was awarded to Paul Hermann Müller. The Nobel Assembly at the Karolinska Institute chose to give Müller the award “for his discovery of the high efficiency of DDT as a contact poison against several arthropods”. Topics include the use of DDT to control the spread of insect-borne diseases, the creation of the United States CDC and the Environmental Protection Agency, and bacteria that prevent mosquitos from spreading dengue virus.