If modern activist groups held sway in the mid-nineteenth century, countless multitudes would have died from typhoid fever and cholera. The "miasma" paradigm held that the diseases were caused by foul air arising from putrid matter--and only dogged scientific work by William Budd, John Snow and others finally convinced medical and health authorities that the agent was lethal organisms in drinking water.
Ultimately, the investigators' persistence led to discoveries of Vibrio and Salmonella bacteria, the use of chlorine-based disinfectants for drains, water purification and hand washing, programs that kept sewage away from drinking water supplies, and steady advances in germ and virus theories of medicine.