Health department use of social media to identify foodborne illness - Chicago, Illinois, 2013-2014.

An estimated 55 million to 105 million persons in the United States experience acute gastroenteritis caused by foodborne illness each year, resulting in costs of $2-$4 billion annually. Many persons do not seek treatment, resulting in underreporting of the actual number of cases and cost of the illnesses. To prevent foodborne illness, local health departments nationwide license and inspect restaurants and track and respond to foodborne illness complaints.