Two of four confirmed cases of E. coli O157:H7 involving residents of Boone County, Missouri could be related to the St. Louis outbreak, the Columbia/Boone County Department of Public Health said Friday.

Columbia/Boone health officials say testing is not complete. In one case matching the outbreak strain, the person has not been to St. Louis lately, so the case technically does not meet the outbreak criteria established by the federal Centers for Disease Control (CDC).

In the other case, the Boone County resident recently returned from St. Louis, but those test results also are still underway.  

After the Missouri Department of Health and Senior Services (DHSS) reported Thursday that three confirmed E. coli cases in Boone County were not connected to the St. Louis outbreak, further work confirmed a fourth case and turned up the possible connection to the outbreak 125 miles to the east.

Columbia/Boone County health officials have also sent a fifth specimen to the state health lab for confirmation, but those test results are still pending.

Home of the main campus of the University of Missouri, Columbia is midway across the state, putting it within easy reach of both St. Louis to the east and Kansas City to the west.

The city/county health officials in the college town are urging anyone experiencing symptoms such as stomach cramps, diarrhea or nausea to seek medical attention.

Missouri health officials have not yet been able to identify the source of the E. coli bacteria that is making people in the state sick. The St. Louis outbreak involves at least 25 cases, including 19 that have required hospitalization. One case of hemolytic uremic syndrome (HUS), which threatens the kidneys, is also being treated.