Epidemiological case studies are based on historical events and include epidemiologic methods being practiced at the time. Aside the historical nature of this content, the ways that are documented on this website are also noncurrent practices in some settings. As a number of the practices are still used, they continue to offer educational value. These case studies are interactive exercises developed to show epidemiological principles and practices. They are based on real-life outbreaks and public health issues and were developed together with the first investigators and consultants from the Centers for disease control and prevention (CDC).