The Broad Street pump revisited: dairy farms and an ongoing outbreak of inflammatory bowel disease in Forest, Virginia

On December 4, 1854, at a meeting of the London Epidemiological Society, Dr. John Snow presented a map illustrating multiple cases of cholera deaths earlier that year in an area of London near a now famous pump on Broad Street (Figure 1)[1]. The word "outbreak" was used to describe the deaths from cholera occurring within houses that obtained water from the Broad Street pump, and the map of the cases' houses in relationship to the pump helped establish that an infectious microorganism in the pump's water was the cause of the cases' cholera.Multiple cases of Crohn's disease occurring within a geographic area have been referred to as clusters rather than outbreaks, but some investigators of these clusters have concluded that some cases of Crohn's disease, like cholera, are caused by an infectious microorganism [2]; a microorganism present in unpasteurized milk [3] and cheese [4], and in animal feces that contaminate well [4,5] and river water [6,7] and lakes and ponds used for swimming and other recreational purposes [7].Mycobacterium avium subspecies paratuberculosis (MAP), the cause of a chronic diarrheal disease in dairy cattle called Johne's ('Yo-knee's') disease, is present in an infected dairy cow's feces and milk [8], and could play an etiologic role in Crohn's clusters. Some investigators have proposed that MAP may cause some cases of Crohn's disease [2,8] and the other major form of inflammatory bowel disease ulcerative colitis [9].While the existing medical literature suggests MAP is transmitted to humans through milk and milk products, it seems more likely that most people are exposed to the organism through water contaminated with bovine fecal matter. The symptoms of ulcerative colitis and Crohn's disease are similar to many enteric infections, and most enteric infections are transmitted via the fecal-oral route.Adult male dairy farm workers have more than an eightfold increased risk of developing ulcerative colitis [10]; however the following is the first