What is an example of laboratory evidence in an outbreak investigation?

• A. The germ that caused illness is found in a food item collected from a sick person's home, a retail location, or from the food production environment
• B. Same DNA fingerprint linking germs found in foods or production environments to germs found in sick people
• C. Both A and B
• D. Interviews with sick people

Answer: (C)

In an outbreak investigation, laboratory evidence includes detecting the actual pathogen in a suspected source and using genetic analysis to show the same strain is present in both the source and the sick people. Finding the germ in a food item or in the production environment shows the source contains the agent. Using a DNA fingerprint to link germs found in foods or production environments to germs found in ill individuals strengthens the connection between the source and the cases, making it a direct, laboratory-based link. Interviews with sick people provide important information about exposure patterns, but they are epidemiologic evidence, not laboratory evidence. Therefore, both finding the germ in a food item or environment and demonstrating the same DNA fingerprint in sources and cases are examples of laboratory evidence.