Escherichia Coli O157:H7 2002

Table 1. E. coli O157:H7 Cases by Race and Sex, Indiana, 2002

  2002 1998-2002
Cases Rate* Cases
Total 87 1.41 506
   White 63 1.2 351
   Black 4 0.8 18
   Other 0 0 3
   Not Reported 20   134
   Male 41 1.4 263
   Female 46 1.5 230
   Not Reported 0   13

*Rate per 100,000 population based on the U.S. Census Bureau’s population data as of July 1, 2002

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 2002, 87 cases of E. coli O157:H7 infection were reported in Indiana, for a rate of 1.4 cases per 100,000 (Table 1). This is approximately the same rate reported in 2001. Figure 1 shows the number of reported cases per year for 1998-2002. Incidence of disease was greatest during the summer months. Figure 2 shows the number of reported cases per month. As shown in Figure 3, age-specific rates were highest among preschoolers aged 1-4 years (3.5), adults aged 80 years or older (2.9) and adolescents aged 10-19 years (1.7). Females (1.5) were slightly more likely to be reported than males (1.4). The rate for whites (1.2) was higher than that for blacks (0.8) or other races (0.0); however, 20 cases (23%) did not report race data.

The incidence rates were highest among the following counties reporting five or more cases: Bartholomew (7.0), Johnson (5.8), and St. Joseph (2.2). Figure 4 shows counties reporting five or more cases in 2002. There were no reported outbreaks of E. coli O157:H7 infection in Indiana in 2002.

Of the 87 confirmed E. coli O157:H7 cases reported in 2002, 10 (11.5%) reported developing HUS. All were white, five were male, and five were female. Four cases were 1-4 years old, three were 5-9 years old, one was 10-19 years old, and two were adults. One case died.

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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