The King County Public Health Department is reporting that a child from the city of Mercer Island, WA, has fallen ill with a presumptive infection of E. coli O157:H7. The child has not been hospitalized. The city has been under multiple water boil advisories for possible E. coli contamination, including one that is still in effect. After the first boil advisory was lifted on Sept. 29, a follow-up test on Oct. 2 once again found E. coli in the water. The city then issued another water boil advisory and ordered all 62 restaurants, cafes and delis in the city to close. That advisory is still in place. At this point, the health department can’t say for certain that there’s a link between the child’s infection and the problem with the city’s water. The department pointed out that E. coli can come from a variety of sources other than water, including ground beef, unpasteurized milk, and fresh produce. The child reportedly has multiple sources of potential exposure, including Mercer Island water and food that has the potential to be contaminated with E. coli. “We may never be able to definitively link this case to a particular source,” said Dr. Meagan Kay, medical epidemiologist for the agency. If any additional cases of infection arise in or around Mercer Island, the probability of determining the source will increase. “At this time, we do not have evidence of an increase in gastrointestinal illnesses among Mercer Island residents,” the agency stated. The health department plans to continue monitoring for any potential E. coli illnesses in the area. Symptoms of E. coli infection include stomach cramps and diarrhea, which can turn bloody in severe cases. Children, the elderly, and immunocompromised individuals are at an increased risk of acquiring severe infections. Anyone experiencing symptoms of an E. coli infection is advised to contact a healthcare provider.