Five people have confirmed infections with Shiga toxin-producing E. coli, and health officials in San Luis Obispo County, California, are investigating Brookshire Farms in San Luis Obispo as the possible source. Anyone who visited the farm from October 16 through 26 should watch for symptoms, the county's public health department says. The farm has closed voluntarily while the investigation continues, and the source of the infections has not been identified.

Three of the patients are young children who developed hemolytic uremic syndrome, a complication that can lead to kidney failure, according to a notice the county sent to doctors on October 27.

Symptoms and when to call a doctor

The county asks anyone who visited Brookshire Farms during the exposure window and develops cramping stomach pain or bloody diarrhea to contact a health care provider. Symptoms usually appear 3 to 5 days after exposure but can take up to 10 days, so a visit near the end of the window could still lead to illness in the first days of November.

Children under 10 face the highest risk of complications. Anyone with bloody diarrhea, severe abdominal pain or signs of dehydration should seek medical care, the county says. In its notice to doctors, the county warns that antibiotics are thought to speed up or worsen the illness in these patients and says anti-diarrhea medicines may also raise the risk of complications.

How the bacteria spread

People can pick up the bacteria from contaminated food or water, from touching infected animals, or from traces of animal or human feces, and the germs can linger in the environment for months, according to the provider notice. Cattle carry them most often, but goats, sheep, pigs and deer can carry them too while appearing healthy.

The investigation has not tied the cases to animals or to any food. For families visiting farms, petting zoos or other animal exhibits this fall, the CDC's farm animal guidance recommends:

  • Washing hands with soap and water right after touching animals or anything in their pens, and using hand sanitizer only when soap and water are not available.
  • Supervising young children while they wash.
  • Not eating or drinking in animal areas.
  • Leaving strollers, pacifiers, bottles, sippy cups and toys out of animal areas.

What happens next

The county says more cases may be identified as investigators follow up with people who may have been exposed, and it urges anyone contacted by investigators to answer their questions. "We encourage anyone who may have been exposed and is experiencing symptoms consistent with E. coli infection to seek immediate medical attention," County Health Officer Dr. Christy Mulkerin said in the release.

Doctors who suspect a case are asked to report it to the county at 805-781-5500 on weekdays or 805-781-4553 after hours and on weekends.