8. Prevent Future Outbreaks Through Summarizing, Interpreting, and Reporting Findings

Reporting a Waterborne Disease Outbreak

Outbreak investigations are important learning opportunities for recognizing threats to safe water, uncovering contributing factors to water contamination, and identifying ways to prevent future outbreaks. Data from waterborne disease outbreaks provides crucial information for understanding risk factors for waterborne disease and for identifying ongoing and emerging threats. Additionally, these data facilitate evaluation of any progress made in the improvement and in the provision of, as well as access to, safe water. Drinking water outbreak data have been used to inform the development and implementation of drinking water regulations. Recreational water outbreak data have been used to identify emerging threats and develop a model aquatic health code. Compiling and sharing outbreak reports supports public health efforts to protect the public from waterborne disease.

Reporting outbreaks:

  • Local Health Departments
    • Most states and territories require that local health departments report outbreaks of suspected foodborne and waterborne illness to their state or territorial health department.
  • State and Territorial Health Departments
    • Public health agencies in all 50 states, the District of Columbia, U.S. territories, and Freely Associated States have the primary responsibility of identifying and investigating waterborne outbreaks, as well as using a standard form to report outbreaks voluntarily to the CDC. Waterborne disease outbreaks became nationally notifiable in the United States in 2009.
    • State and territorial health departments can report all waterborne disease outbreaks to the National Outbreak Reporting System (NORS). Individual cases of harmful algal bloom (HAB)-associated human or animal illness and HAB events can be reported in the One Health Harmful Algal Bloom System (OHHABS).

Learning from Outbreaks

Following a public health investigation gathering and sharing information about the investigation, the steps taken, and the results can be used to aid in future investigations. This is why health departments voluntarily submit de-identified outbreak data to CDC. The reported information includes a summary of the number of outbreak-associated illnesses, hospitalizations and deaths, as well as the etiologic agent(s), implicated water venue or system, water settings, environmental data and contributing factor information.

CDC epidemiologists review the outbreak data and follow up with the health departments to verify the information and to gather additional information as needed. Periodically, CDC and EPA researchers analyze the outbreak data and report on outbreak characteristics and trends. Waterborne disease outbreak reports have been published since the 1970s. Outbreak data are available online through the NORS Dashboard, a publicly available data visualization tool that also has a dataset download feature. See CDC’s Waterborne Disease and Outbreak Surveillance reporting website:  https://www.cdc.gov/healthywater/surveillance/index.html

Public health agencies, policymakers, and the general public can access waterborne disease outbreak reports and data to inform development of prevention efforts, namely through evidence based health communication and policy efforts targeted to prevent future spread and occurrence of waterborne disease.

Improving outbreak response:

To improve future outbreak responses, health departments should consider conducting an after-action review following an outbreak investigation. Inviting key partners from the outbreak to discuss the outbreak timeline, communication processes, control measures, and other outbreak outcomes can help determine if there were deficiencies within the organization processes that can be improved.  Working with partners to document lessons learned and publish novel findings can further strengthen partnerships and improve future outbreak responses.