In the spring of 1993, an unexplained illness struck the residents of Milwaukee, Wisconsin. Four hundred thousand people developed a serious gastrointestinal illness, 4,000 were hospitalized and, by the time the epidemic was under control, more than 100 people were dead. Health officials suspected it was influenza, but it proved to be more serious and more difficult to identify. Medical Detectives, Season 2, Ep 13. (thetvdb.com)