MMWR. 1995;44:501-503 1 figure omitted
DURING February-March, 1994, four persons in Helena, Montana (1995 population: 24569), developed bloody diarrhea and severe abdominal cramps.
Stool cultures for Salmonella, Shigella, Campylobacter, and Escherichia coli O157:H7 were negative; however, sorbitol-negative E. coli colonies were identified in stools from all four patients. Isolates from three patients were identified at CDC as a rare serotype—E. coli O104:H21 that produced Shiga-like toxin II. This report summarizes the epidemiologic and laboratory investigations of this outbreak by the Lewis and Clark County Department of Health and Environmental Sciences, the Montana Department of Health and Environmental Sciences (MDHES), and CDC.
A confirmed case was defined as acute infection with E. coli O104:H21 during February 20-May 25, 1994—based on stool culture or serologic evidence—in a resident of or a visitor to the Helena area. A suspected case was defined as onset of bloody diarrhea or abdominal cramps during the
Outbreak of Acute Gastroenteritis Attributable to Escherichia coli Serotype O104:H21— Helena, Montana, 1994. JAMA. 1995;274(7):529-530. doi:10.1001/jama.1995.03530070027011