Escherichia Coli O157:H7 2003
*Rate per 100,000 population based on the U.S. Census Bureau’s population data as of July 1, 2003
Escherichia coli O157:H7 infection is a bacterial disease usually transmitted through raw or undercooked foods of animal origin or foods cross-contaminated by animal products or feces. It has commonly been associated with raw or undercooked hamburger, unwashed produce, and unpasteurized juices. Outbreaks have also been attributed to swimming in or drinking untreated surface water. The infection can also be transmitted person to person and is a special concern in the daycare setting. Rarely, patients can develop hemolytic uremic syndrome (HUS) as a result of E. coli O157:H7 infection. Symptoms of this disorder include kidney dysfunction, hemolytic anemia, and platelet loss; HUS can be fatal. Populations at most risk include young children, the elderly, and those with weakened immune systems. Approximately 2-7 percent of E. coli O157:H7 cases will develop HUS.
In 2003, 91 cases of E. coli O157:H7 infection were reported in Indiana, for a rate of 1.50 cases per 100,000 population. This is approximately the same rate reported in 2002. Figure 1 shows the number of reported cases per year for 1999-2003. Incidence of disease was greatest during the summer months. Figure 2 shows the number of cases per month in Indiana for 2003. As shown in Figure 3, age-specific rates were highest among preschoolers aged 1-4 years (5.8), followed by infants less than 1 year of age (3.6), and children aged 5-9 years (3.0). Females (1.8) were more likely to be reported than males (1.1). The rate for other races was higher (1.3) than that for whites (1.1) and blacks (0.8); however, 25 cases (27%) did not report race data.
The incidence rates were highest among the following counties reporting five or more cases: Henry (18.8), St. Joseph (3.7), and Hamilton (2.9). Figure 4 shows counties reporting five or more cases of E. coli O157:H7 in 2003. There were no reported outbreaks of E. coli O157:H7 infection in Indiana in 2003.
Of the 91 confirmed E. coli O157:H7 cases reported in 2003, 4 (4.4%) reported developing HUS. All cases survived.
It is recommended that all clinical laboratories routinely screen all stool specimens for sorbitol-negative E. coli strains. Lack of sorbitol fermentation in E. coli bacteria is a biochemical marker for the O157:H7 serotype. The ISDH requests that clinical laboratories submit all E. coli O157:H7 or sorbitol-negative E. coli isolates to the ISDH Laboratories for free confirmation and subtyping services.
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