Water sources can become contaminated with Salmonella and other pathogens in a variety of ways. Water that is downstream from cattle pastures, feed lots, or barns can easily become contaminated with Salmonella from runoff. When lakes become contaminated, several weeks or months can pass before water quality conditions improve or return to normal. When municipal water sources become contaminated, systems must be flushed to ensure all bacteria has been eliminated from the system, and chlorine levels high enough to kill any Salmonella must be introduced.
Pools can become contaminated with Salmonella by animal feces or through fecal contamination from an infected person. Children who are not yet toilet trained and soil diapers while playing in water have been identified as the source of E. coli and Shigellaoutbreaks. Proper chlorine levels must be maintained to prevent the spread of Salmonella and other pathogens in pools and at water parks.
In 2008, the Colorado Department of Public Health and Environment (CDPHE) issued a bottled water advisory for residents of Alamosa, Colorado, and area residents after Salmonella contamination in the Alamosa municipal water system was discovered. CDPHE arranged for the Alamosa municipal water system to be flushed and tested to determine when the water would again be safe to drink. People affected were advised to:
- Use bottled water for cooking, drinking, brushing teeth, making ice, washing dishes, and for preparation of baby formula
- Exercise caution not to ingest water during bathing and showering
- Cease commercial food preparation unless approved by a local public health agency
- Use only prepackaged foods that do not require additional preparation other than heating in original containers
- Apply hand sanitizer after washing hands
- Use disposable gloves to touch food
- Use frozen or canned produce
- Purchase potable ice
- Use paper plates, napkins, cups, plastic spoons, forks, and knives
Toward the end of the outbreak, the City of Alamosa reported 442 cases of Salmonella. Overall, state health experts estimate that up to 1,300 people may have been ill in the town of 8,900. Sixteen people were hospitalized due to Salmonella infection, and one death may have been related to the consumption of Salmonella-contaminated water.
The health department's final report, released in November of 2009, contains a comprehensive look at the Salmonella outbreak, the response to the outbreak, and the conclusion of the 18-month investigation into how the city's drinking water became contaminated with animal feces. The investigation involved a detailed review of the water system; historical records; and interviews with city of Alamosa personnel, local health officials and responders to the outbreak. See Municipal Water System Salmonella Outbreak Litigation.