7.6 Recognition of Outbreaks/Actions to Be Taken if an Outbreak Is Suspected

Any illness that could be passed from person to person or caused by a widespread exposure that has an unexpected activity level should be reported.

Respiratory illnesses like influenza, digestive illnesses like vomiting or diarrhea, and rash illnesses like chickenpox or staph are the most common causes of outbreaks in social situations.

Critical environmental factors (e.g., carbon monoxide, pesticide intoxication) may also contribute to outbreaks. Even if no particular disease has been identified, the local health department should be alerted when an epidemic is suspected.

The steps in most investigations are as follows:

• Prepare the investigation
• Confirm the diagnosis and the outbreak’s presence
• Create a case definition and look for cases
• Use evocative epidemiology to determine the cases’ attributes, changes in illness regularity over time, and discrepancies in incidence rate based on location
• Make hypotheses about the cause or source
• Evaluate and perfect hypotheses and conduct research testing if required
• Implement preventive and control measures
• Present the findings

Some of the steps may be completed simultaneously, and the order may change depending on the situation. For example, if new cases continue to emerge and steps can be taken to control the outbreak and prevent further cases, prevention and management measures would undoubtedly take precedence.