ST. LOUIS COUNTY, Mo. — The St. Louis County Department of Health (DPH) is investigating an outbreak of E. coli among students and parents at Rockwood Summit High School who attended an off-campus event.

There are 19 associated cases, according to DPH. Some cases have been laboratory confirmed and other people have experienced compatible symptoms, but have not been tested.

The students and parents have been exposed to the O157 strain of E. coli, which produces a powerful toxin that causes severe illness such as diarrhea and painful abdominal cramps, according to DPH.

E. coli O157 infections also can cause a severe complication called Hemolytic Uremic Syndrome (HUS) in young children and the elderly, which can lead to kidney failure, neurologic damage, and in some cases, death.

DPH says antibiotics should not be used to treat E. coli O157 because it can increase the likelihood of developing HUS.

DPH communicable disease investigators and environment health inspectors are working to identify a possible source of exposure.

Outbreak investigations are conducted through interviews by those who are sick and asking about their symptoms and possible exposures such as food history, recent travel, events attended, animal contact, etc.

 An outbreak that may be associated with a specific event or location, investigators also may interview people who did not get sick, but attended the same event or location.

DPH partners with relevant schools, restaurants and workplaces to identify additional cases, track down potential exposure sources and implement necessary control measures, according to DPH.

The investigation is ongoing.