|Image by rogue2408 via Flickr|
Large-scale collection of sewage began more than 2400 years ago with the construction of the Cloaca Maxima in Rome. The Dejecti Effusive Actio was one of the earliest sanitation laws, and it fined Romans who hurt passers-by when they tossed or poured their wastes into the streets. However, much of the Romans' progress in sanitation was forgotten until the 19th century when modern waste treatment began.
Polio occurred in ancient Rome (some say Claudius was a victim, although this may be doubtful); it later largely disappeared in Europe and re-emerged in the 19th century (anecdotally supporting the sanitation hypothesis related to polio immunization).