An E. coli-contaminated lake in Nevada County, Calif., linked to the illnesses of 14 people will remain closed until at least Aug. 23, county officials announced Wednesday.

Hannah Knowles of the Sacramento Bee reports authorities closed all of Lake Wildwood’s public beaches last week after water testing confirmed reports linking E. coli infections to the lake’s Main Beach, also called Commodore Park. The county also advised against any swimming in the lake.

As of Wednesday, 14 people – 11 children and three adults – are believed to have contracted E. coli after visiting the Main Beach and, in many cases, ingesting lake water, according to the Nevada County Public Health Department. Lab results so far confirm 11 of those 14 cases are connected to the lake’s bacteria.

By Tuesday, nine people had been hospitalized in connection with the outbreak, county Public Health Coordinator Patti Carter said. Six had been discharged by Wednesday evening.

Four sickened children developed a serious condition called hemolytic uremic syndrome, which can lead to potentially fatal kidney failure and anemia.