Many agencies and organizations in the US use April to showcase what public health does. I had intended, as April drew to a close, to write a post highlighting public health, and its relationship with social marketing. Then, the novel H1N1 flu began to emerge, and provided public health with the opportunity to showcase itself! (Although my involvement in the response delayed my completing this post.)
Though one can trace the historical roots of public health back to classical times, epidemiology--the scientific basis for public health--traces back to the work of John Snow. (Epidemiology, by the way, is the science of how and why diseases spread through populations.) John Snow was a physician in 19th Century London who used the emerging discipline of epidemiology to discover and remediate the source of a deadly cholera outbreak. Without knowing about the bacterium, Dr. Snow was still able to identify the source of infection--a contaminated community water pump--and execute an intervention to quell the epidemic: he removed the handle from the offending pump! (Thus, one of the first "modern" public health interventions was a change in the environment!) The methods our current day Epidemic Intelligence Surveillance personel use to trace the source and spread of H1N1, while more sophisticated, still follow in John Snow's footsteps. Our modern public health personnel also exhibit the same tenacity, caring and passion, as he! (Some things don't change.)
Several years ago, I had work in London. Being the good public health geek that I am, I asked my host to help me find the center of John Snow's work: the famous Broad Street Pump in Soho! (Its near Carnaby Street, the center of 1960s London, for all you old hippies.) At the site of the pump, there is an appropriate plaque, with a stone set in the 
sidewalk to mark the pump's location. There is also the John Snow Tavern, the upstairs of which hosts a collection of memorabilia, as well as the John Snow Society, which celebrates his work. The book, The Ghost Map, by Steven Johnson, provides a very riveting, readable account of the outbreak and of Snow's work.
Public health tourist that I am, I had my wife photograph me at various spots around the pump's location! I have been extraordinarily proud of 
public health's response to the novel H1N1 flu outbreak. I think Dr. Snow would smile, too!
