At least 11 visitors to this summer’s Minnesota State Fair have suffered E. coli infections, and disease investigators say that contact with animals in the popular Miracle of Birth Center is the leading culprit.

Six of the sickened individuals, who ranged in age from 2 to 43, were hospitalized, and one suffered hemolytic uremic syndrome, a severe complication that affects the blood and kidneys.

Interviews with 10 patients found that eight had visited the Miracle of Birth Center, an attraction that features baby animals and often live births.

Not all of them actually touched the calves, goats, sheep or piglets in the center, but the fecal bacteria could have spread from one of the animals to railings or other surfaces, said Kirk Smith, an epidemiologist with the Minnesota Department of Health. “There’s been all kinds of outbreaks where people touched a contaminated surface like a fence rail or the bleachers. These germs have a way of making their way around a building.”

The risk of exposure is low now that the fair has ended, but health officials issued an alert Tuesday so that doctors can be on the lookout for additional cases, and they reminded the public about the importance of hand-washing and hygiene to prevent infection. Smith noted that sickened people also could still pass the infection to other people, even after they have recovered. E. coli outbreaks often occur this way in child care facilities.

DNA testing is underway to verify that all 11 people had the same strain of E. coli O157, which Smith said is “notorious” for causing severe illnesses and complications. Its possible the two sickened people who didn’t go to the Miracle of Birth Center had unrelated infections.

Minnesota reports roughly 130 cases each year of E. coli O157, and some are typically associated with agricultural events such as county fairs. Smith said he couldn’t recall an outbreak at the State Fair, which has ample hand-washing and sanitizer stations, since a 2007 event associated with the cattle barn. The fair also had an outbreak of H1N1 influenza, or swine flu, in 2009 that resulted in an evacuation of teens from the 4-H dormitory.

Fair officials said in a statement that they would consider additional efforts, beyond signage and hand-washing stations, in 2020, adding that the “health and safety of our fair guests and exhibitors are always a top priority.” A record 2.1 million people attended the fair this year.

State health officials are following up to make sure animals that were on display at the Miracle of Birth Center aren’t now a part of any public exhibits. Regardless, Smith said people shouldn’t take food into animal exhibits, and should always wash their hands after leaving them.

Stomach cramps and diarrhea are the most common symptoms of infections with E. coli, which is spread when people touch animals or surfaces contaminated with fecal matter. E. coli can spread in the air through contact with sawdust or other heavy particles, but presents the greatest risk when those particles settle on high-contact surfaces such as railings, counters and door handles. Sometimes, people get E. coli on their shoes and suffer transmission after taking their shoes off.

“It’s a strong reminder for people going to pumpkin patches, apple orchards, or other agricultural operations that have livestock, to be aware,” Smith said. “Even healthy animals can carry E. coli O157. It does not make them ill. You need to wash your hands.”