Five people who visited a pumpkin patch in San Luis Obispo County, California, have a dangerous form of E. coli, Fox News, ABC News and SFGATE report. Three of them are children being treated in intensive care, the outlets report.

The county health department says it is looking into a link to Brookshire Farms, which has a pumpkin patch, a corn maze and hayrides, ABC News reports. All five patients had visited the farm, a health department spokesperson said. Two of the sick are adults, ABC News reports.

Officials say people were likely exposed between October 16 and October 26, the outlets report. Anyone who visited in that time and gets cramps or bloody diarrhea should call a doctor, the county says. Symptoms often start three to 10 days after contact.

"We are working diligently to identify the source of these infections to protect the health of our community," County Health Officer Dr. Christy Mulkerin said, Fox News and SFGATE report. The farm is closed for now and is working with officials, the outlets report.

This kind of E. coli makes a toxin that can lead to a serious kidney illness, the outlets report. Children under 10 face the highest risk of that, ABC News reports. A UC San Francisco expert said antibiotics are not usually given, because killing the germ can release more toxin, SFGATE reports.

Health officials say more cases may be found as the work goes on, ABC News reports. They have not yet found the exact source of the illness, the outlet reports.

What we know: Five people who visited Brookshire Farms are sick, and three children are in intensive care.
What we don't: What caused the illness and whether more people are sick.