Outbreak Investigation Guidelines

Gastrointestinal outbreak investigation guidelines

Please report all outbreaks of enteric illness to us and/or the appropriate local public health agency within 24 hours after the outbreak is detected. Local public health agencies should call us at 303-692-2700 to report outbreaks and obtain an outbreak ID number, especially before sending specimens to the state public health laboratory for testing.

Here are some examples of outbreaks that should be reported to us:

Suspected C. perfringens after a wedding meal.
E. coli O157 associated with visiting a petting zoo.
Shigella at a child care center.
Cryptosporidium at swimming pool.
Suspected norovirus outbreak at a long-term care facility or summer camp.

Resources to use during the investigation

Questionnaire for retail food establishment food handlers (for use with outbreaks where the suspected setting is a retail food establishment, like a restaurant, caterer, grocery store, etc.) |In Spanish.
Questionnaire for managers of retail food establishments (for use with outbreaks where the suspected setting is a retail food establishment, like a restaurant, caterer, grocery store, etc.) |In Spanish.
Specimen collection.
CDC’s OutbreakNet website (sample questionnaires, outbreak data, many other resources).
Council to Improve Foodborne Outbreak Response (CIFOR) and the Guidelines for Foodborne Disease Outbreak Response developed by the CIFOR.
FDA “Bad Bug Book”(online handbook with basic facts about foodborne pathogens and toxins).
Bleach concentrations for suspect and confirmed norovirus outbreaks.
Line list template.
Guidelines for Restaurants: Management of Norovirus Outbreaks in Retail Food Establishments (opens in new window)(for use by retail food establishments during a norovirus outbreak)
Guidelines for Public Health Agencies: Management of Norovirus Outbreaks in Retail Food (opens in new window)Establishments (for use by public health agencies when responding to norovirus outbreaks in retail food establishments)
Bleach dilution calculator tool.
Media Communication toolkit (two-page handout providing public health professionals with tips, tools, and resources for successfully interacting with the media during an outbreak)
Industry Relations toolkit (two-page handout that provides public health professionals with tips, tools, and resources for successfully interacting with a company or business implicated in a foodborne illness outbreak)

Outbreak reporting forms

When the outbreak is over, it’s very important to complete an outbreak report form with appropriate summary data so the outbreak can be officially reported to the CDC. When the outbreak is over, please fax the appropriate form to us at 303-782-0338. We’ll report the data to the CDC. Depending on the route of transmission, use one of the following three forms:

Most outbreaks of enteric illness should be reported using the Enteric Illness Report Form (NORS Form).This includes outbreaks with the following routes of transmission:
- Foodborne.
- Waterborne.
- Animal contact.
- Environmental contamination.
- Person-to-person transmission (e.g., norovirus at a summer camp or salmonella in child care center).
- Video instructions for completing NORS form.
- CDC guidance for using the NORS form:
  - NORS appendix (key to codes used in the NORS form).
  - CDC instructions for completing the NORS form.
Outbreaks that meet all three of the following criteria can be reported using one of our shorter outbreak report forms:
- Etiology is suspected or confirmed norovirus/viral gastroenteritis.
- The primary route of transmission is person-to-person. If a food or waterborne source is suspected, a more in-depth investigation (and NORS form) is needed to try to identify the source.
- Outbreak setting is a healthcare facility, long-term care facility, assisted living, childcare center/preschool, school, camp, or other similar setting.
  - Gastrointestinal Outbreaks in Schools, Child Care Centers and Camps
  - Gastroenteritis (Norovirus) in Healthcare and Residential Facilities
Any waterborne outbreak should be reported using the NORS form. This includes outbreaks related to drinking water or to recreational water, such as a lake or swimming pool.
Outbreak summaries should be submitted for all outbreaks except for person-to-person Norovirus/Viral Gastroenteritis in long term care facilities, assisted living centers, childcare centers, schools, camps and other similar settings. Final outbreak summaries should be submitted to CDPHE at cdphe_food_enteric_water_diseases@state.co.us(opens in new window).
- Outbreak summary report template