Outbreak of Escherichia coli O157:H7 Infections Associated with Dairy Education Event Attendance - Whatcom County, Washington, 2015.

On April 27, 2015, the Whatcom County Health Department (WCHD) in Bellingham, Washington, was notified by a local laboratory regarding three children with presumptive Escherichia coli O157 infection. WCHD interviewed the parents, who indicated that all three children had attended a dairy education event held in a barn April 20–24, 2015, during a school field trip. WCHD, the Washington State Department of Health, and CDC investigated to determine the magnitude of the outbreak, identify risk factors and potential environmental sources of infection, and develop recommendations. A total of 60 cases (25 confirmed and 35 probable) were identified, and 11 patients were hospitalized.