Published: Apr 27, 2012 2:14 PM EDT

JEFFERSON CITY, Mo. (AP) - Missouri health officials say they have narrowed their investigation into E coli in Missouri to 12 cases with similarities.
The state Department of Health and Senior Services previously reported 15 confirmed cases of E coli, mostly in central Missouri.
A department spokeswoman says the investigation will now concentrate on 12 cases with similar lab results, geographic proximity and case history.
The Columbia Tribune reports eight people recently sickened by a strain of E. coli reported consuming raw milk from a farm in Armstrong. But samples of raw dairy materials taken from the Howard County farm all tested negative for the bacteria.
Columbia/Boone County health officials say one of four cases in the county, a 2-year-old child, remains hospitalized.
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