E. coli outbreaks in Halton, Niagara and Waterloo that have sickened hundreds have been linked by DNA tests showing they share the same rare genetic makeup. Public health officials are also investigating whether E. coli cases at the University of Guelph have the same DNA fingerprint. Of the cases linked in Ontario, 13 have been confirmed in the Niagara Region, three in Halton and two in Waterloo. Another 106 cases in Niagara and Halton are being investigated. In the United States, the genetic code recently showed up in five cases of the food-borne pathogen in Southern California, South Dakota and New Jersey