Capitola Beach in Santa Cruz County is temporarily closed due to an outbreak of E. coli that has sickened nine children across the Bay Area, Santa Cruz County Health Services Agency said Tuesday.

Santa Cruz County Public Health Division has been notified of nine cases of E. coli O157 infection, the county said. Four cases involve Santa Cruz County residents, while five involve residents of other Bay Area counties. All nine cases are linked, indicating a common source or related exposures.

The group of bacteria known as E. coli O157 can cause severe gastrointestinal illness, including diarrhea that may be bloody, abdominal cramps and vomiting. Some infections can lead to serious complications, particularly among young children.

According to the county, the source of the outbreak remains unknown, and public health officials have determined all exposures likely occurred at Capitola Beach or in surrounding waterways.

The city of Capitola is temporarily closing Capitola Beach while the investigation continues. The closure is intended to reduce potential exposure while officials gather additional information, the county said.

Environmental sampling has been conducted at four locations in and around Soquel Creek and Capitola Beach, including an upstream location near Nob Hill, the jetty, Soquel Creek Lagoon and the flume where water enters Monterey Bay.

Additional E. coli testing is planned as the investigation continues.

Katy St. Clair got her start in journalism by working in the classifieds department at the East Bay Express during the height of alt weeklies, then sweet talked her way into becoming staff writer, submissions editor, and music editor. She has been a columnist in the East Bay Express, SF Weekly, and the San Francisco Examiner. Starting in 2015, she begrudgingly scaled the inverted pyramid at dailies such as the Vallejo Times-Herald, The Vacaville Reporter, and the Daily Republic. She has her own independent news site and blog that covers the delightfully dysfunctional town of Vallejo, California, where she also collaborates with the investigative team at Open Vallejo. A passionate advocate for people with developmental disabilities, she serves on both the Board of the Arc of Solano and the Arc of California. She lives in Vallejo.