Investigating and Reporting

Investigating Outbreaks

Public health officials investigate outbreaks to control them and prevent additional illnesses and to learn how to prevent similar outbreaks from happening in the future. Anyone who suspects an outbreak is occurring should contact their local or state health department.

The public health community works to detect, investigate, control, and prevent future waterborne disease outbreaks. The 8 steps in an outbreak investigation are

1. DETECT a possible outbreak
2. DEFINE and FIND cases
3. GENERATE hypotheses
4. TEST hypotheses using epidemiology, clinical data, and environmental investigation
5. IDENTIFY source of outbreak
6. CONTROL outbreak through remediation and outreach
7. DECIDE outbreak is over
8. PREVENT future outbreaks through summarizing, interpreting, and reporting findings

Several steps may happen at the same time in an outbreak investigation. Once a waterborne disease outbreak investigation ends, public health departments report outbreaks to CDC’s Waterborne Disease and Outbreak Surveillance System (WBDOSS) using a standard reporting form.

Reporting Outbreaks

Waterborne disease outbreaks became nationally notifiable in the United States in 2009. Public health agencies in all 50 states, the District of Columbia, U.S. territories, and Freely Associated States have primary responsibility for identifying and investigating waterborne outbreaks and reporting outbreaks voluntarily to CDC. From 1971 to 2008, outbreaks were reported using a paper form. Since 2009, outbreaks have been reported electronically through CDC’s National Outbreak Reporting System (NORS). WBDOSS collects data reported to NORS on waterborne disease and outbreaks associated with recreational water, drinking water, and other non-recreational water exposures.