One defining feature of the E. coli O145 outbreak linked to Freshway lettuce is its apparently high hospitalization rate. Generally, non-O157 strains of E. coli cause foodpoisoning illnesses severe enough to require hospitalization in .295% of cases, and cause death in .083% of cases. See article by Mead et al. In the lettuce E. coli O145 outbreak, reports suggest that, of the 19 confirmed and 10 probable cases, 12 have been hospitalized. This is a hospitalization rate of about 41%.
There are clearly many more E. coli illnesses in New York, Ohio, and Michigan than the 19 that are currently recognized by the FDA and CDC. Jose Rodriguez, a health official with the City of Columbus, Ohio, has indicated that 15 people were sickened in the Columbus area, including seven confirmed cases of E. coli that are counted in the FDA and CDC’s current case count. Of these 15 confirmed and probable illnesses, seven people were hospitalized, including five students at Ohio State. This is well over a 50% hospitalization rate among recognized cases in the Columbus area alone.
Another indicator of the virulence of a particular strain of E. coli is its association with hemolytic uremic syndrome (HUS). In the Freshway lettuce E. coli O145 outbreak, at least 3 of the 29 confirmed cases have developed HUS, which is a potentially life-threatening complication. It is estimated that, in the typical shiga-toxin producing E. coli outbreak, up to 10% of cases may develop HUS.