As of Monday morning, June 7, the case-count in the Illinois Subway Salmonella outbreak remains at 34 people. The 34 cases reported eating at Subway restaurants in 14 Illinois counties, including Sangamon, Schuyler, Christian, Bureau, LaSalle, Cass, Champaign, Peoria, Shelby, Warren, Macon, Ogle, Fulton and Tazewell. Subway restaurants in the northeastern and southernmost portions of Illinois do not seem to be associated with the outbreak, as none of the 34 confirmed cases report having eaten at Subway restaurants in those areas. Illnesses are reported to have started between May 14 and May 25 and cases range in age from six-years to 88-years-old.
The specific type of Salmonella involved in this outbreak is a rare serotype called Hvittingfoss. Typically, only one to two cases of this type of Salmonella are seen in Illinois per year. Although there has been no positive or confirmed association with a specific product, the SUBWAY® restaurant chain has voluntarily withdrawn all lettuce, green peppers, red onion and tomatoes, from the suspected dates from its restaurants and has replaced the product with new, fresh produce.
Case-counts in Salmonella outbreaks are often a poor indicator of how large an outbreak really is. For Salmonella specifically, the CDC estimates that the number of actual illnesses–as opposed to only "confirmed" illnesses (i.e. persons having a positive stool sample matching the outbreak strain of bacteria)–is as many as 38.6 times the number of confirmed illnesses. Thus, on the high end, possibly a more accurate estimate of the number of ill people in the Illinois Subway Salmonella outbreak is over 1,300 people, as there are many reasons–including no medical treatment, no stool sample, or a false negative result from a tested stool sample–why ill people may not be counted as confirmed cases.