Sick employees are major contributors to the spread of foodborne illnesses at restaurants and other food establishments, according to a Centers for Disease Control and Prevention report released Tuesday. From 2017 to 2019, the report found, around 40% of foodborne illness outbreaks with known causes were at least partly associated with food contamination by a sick or infectious worker. In 2017, for instance, Chipotle attributed a norovirus outbreak at its restaurant in Sterling, Virginia, to an employee who came to work while ill.