Surveillance provides valuable insights into the foods, germs, and settings linked to foodborne diseases. For more than 30 years, CDC has conducted surveillance for Listeria infections to learn more about the germ, how it causes disease, how it’s spread, and other information to help protect the public from illness. Each of the CDC systems monitoring Listeria serves a different purpose. Together, they provide a comprehensive view of listeriosis in the United States.

How Long Can It Take to Link a Case of Listeriosis to an Outbreak?

Smaller image of Timeline for Linking a Case of Listeria Infection to an Outbreak

Have you ever wondered why it takes a while to hear about cases of Listeria infection after a person gets sick? Or why the number of cases linked to an outbreak can increase for weeks after measures are taken to stop the outbreak? A series of events occurs from when someone eats a food contaminated with Listeria to when public health officials can determine that the person is part of an outbreak. Find out more