Twenty people, including 17 children, from up and down Colorado’s Front Range are suffering from confirmed cases of E. coli, Denver Public Health officials said today. The common thread — all attended the National Western Stock Show held in late January in the Mile High City.

A lab has confirmed 20 E. coli cases but the number is expected to grow, said Chris Urbina with Denver Public Health.

The strain E. coli O157 primarily affected children on the Front Range, from Boulder to El Paso County.

"While the investigation is ongoing, we suspect that these infections are linked to attending the National Western Stock Show, which was held in Denver from Jan. 10 to Jan. 25," the Colorado Department of Public Health and Environment said in a news release.

Although health officials haven’t pinpointed the exact cause of the E. coli, the common denominator in all the cases is the stock show, Urbina said.  For 12th year in a row, the National Western Stock Show attendance topped 600,000–making it one of the largest events of its kind in the nation.

No one from the Stock Show has yet addressed the e. coli outbreak.  Many schools take students to the Stock Show.   For more, go here.