At least five Wisconsin residents have been diagnosed with E. coli, according to the Milwaukee Journal-Sentinel.

Health officials are working to determine whether the Wisconsin cases have a link to earlier cases reported in Minnesota that were traced back to consumption of E. coli-contaminated hamburgers produced by Cargill and sold at Sam’s Club.

One of the victims, an 18-year-old Milwaukee woman, has been confirmed to be suffering from an E. coli infection induced by the same strain of E. coli found in Minnesota children who ate Cargill-brand hamburgers and became ill. The 18-year-old woman linked to the Minnesota cases is the only Wisconsin person whom officials have described.

More tests are being conducted to determine whether any of the other Wisconsin cases share the same strain of E. coli as the Minnesota cases.