King County Public Health has temporarily closed Tibbetts Beach at Lake Sammamish State Park after receiving reports of up to 15 children becoming sick with vomiting and diarrhea.

According to an online update from the King County Health Department’s Public Health Insider blog, the children became sick after swimming at the beach last Friday. Symptoms occurred within 24 hours of visiting the beach.

Public health officials stated Monday they were in the “very earliest stages of investigating the possible outbreak, and do not yet know specifically what type of organism caused the illness.” The department had no reports of hospitalizations or ongoing illnesses.

“Norovirus is suspected, based on the symptoms, the time between exposure and symptoms developing, and the length of the illness,” the department stated in Monday’s blog post, “though we are looking into other potential causes based on the reported symptoms.”

The King County Department of Natural Resources and Parks collected samples on Monday from Tibbetts Beach, Tibbetts Creek and Idylwood Beach.

In an update Tuesday morning, public health officials stated that all reported illnesses are associated specifically with Tibbetts Beach. The health department currently is not recommending closure of other beaches.

Aug. 31 update

Health officials reported Tuesday afternoon that Tibbetts Beach test results came back that showed fecal coliform below the level of concern. Test results for other organisms potentially causing illnesses are still pending.