Translations:Surveillance course participant/64/en
When we measure disease, we have to be sure that everyone is talking about the same thing. This is why we use case definitions, because this gives us a standard set of criteria for deciding what is a case, and what is not. The criteria for a case definition can be based on one or more clinical signs, or other information about the situation (epidemiological data), or laboratory data, or a combination of these things.