Which is the second step in an outbreak investigation?

• A. Detect a possible outbreak
• B. Find cases in an outbreak
• C. Generate a hypothesis
• D. Test the hypothesis

Answer: (B)

Outbreak investigations move from recognizing something unusual to confirming and understanding it. After an initial signal that a cluster of illness might be an outbreak, the next step is to locate and count cases to determine if it truly represents an outbreak and to describe its time, place, and person patterns. This involves applying a case definition, reviewing records, and actively seeking additional cases to expand the count and clarify who is affected. That descriptive step sets the foundation for understanding the outbreak’s scope and directs the search for possible causes. Only after you have a solid set of cases and basic descriptive information do you generate hypotheses about the source and mode of transmission, and then test those hypotheses with further data. So, finding cases in an outbreak is the second step.