St. Louis County health officials are investigating an outbreak of E. coli O157:H7 infections among students and parents at a local high school.

The sick people from Rockwood Summit High School all attended an off-campus event, according to the St. Louis County Department of Health. As of Nov.

14, there were 19 patients. Some of the patients have been laboratory confirmed but others are awaiting test results. The health department has not publicly reported what event the sick people attended.

About E. coli infections Students, staff and parents associated with Rockwood High School — or anyone who hosted people from the school — who have developed symptoms of E. coli infection should seek medical attention and tell their doctor about their possible exposure to the bacteria.

Specific tests are required to diagnose the infections, which can mimic other illnesses. The symptoms of E. coli infections vary for each person but often include severe stomach cramps and diarrhea, which is often bloody.

Some patients may also have a fever. Most patients recover within five to seven days. Others can develop severe or life-threatening symptoms and complications, according to the Centers for Disease Control and Prevention (CDC).

About 5 to 10 percent of those diagnosed with E. coli infections develop a potentially life-threatening kidney failure complication, known as a hemolytic uremic syndrome (HUS). Symptoms of HUS include fever, abdominal pain, feeling very tired, decreased frequency.