A Swimming-Associated Outbreak of Hemorrhagic Colitis Caused by Escherichia coli O157:H7 and Shigella Sonnei

Abstract
In the summer of 1991, simultaneous outbreaks of bloody diarrhea and hemolytic-uremic syndrome caused by Escherichia coli O157:H7 and of bloody diarrhea caused by Shigella sonnei were traced to a lakeside park near Portland, Oregon.