Seven children in King County have been infected with E. coli, a bacteria that produces Shiga toxin.

King County Public Health is currently investigating the outbreak, and has not yet identified foods, restaurants or other shared sources of the outbreak. It’s not know whether these cases are from the same source or not. All cases are currently affecting children under the age of 14, and three are under five years of age, a press release from the health agency states.

All cases were reported between April 22 and May 1 of this year, and all seven children developed symptoms consistent with E. Coli, including abdominal cramping, nausea and vomiting. Six of the children have been hospitalized, including one child who developed a kidney complication, and another who has a suspected case.

Public Health is working with the Washington state Department of Health to conduct testing, and identify whether the are related to cases in other counties. On May 12, the health department confirmed through genetic fingerprinting results (whole genome sequencing) that some of these King County cases are related to cases in other counties within Washington.

If a child develops painful or bloody diarrhea, diarrhea that lasts more than three days or is accompanied by a high fever or decreased urine, Public Health is urging parents to contact their doctor.

E. coli and other foodborne infections happen throughout the year, but may increase in frequency during late spring and summer months.

Anyone sickened by E. coli should not work in or attend child care facilities or preschool, or work in food handling or health care until they’re cleared by Public Health.