Butte County lifts no-swim advisory as dangerous E. coli strain disappears from Big Chico Creek

Big Chico Creek no longer contains a dangerous strain of E. coli that sickened children this summer.

Butte County Public Health made the announcement yesterday, and also lifted its no-swim advisory on the creek.

“In our most recent round of testing … we did not find that subtype of E. coli that we had seen,” said Dr. Jarett Beaudoin, the county’s public health officer. “So that made us feel good about lifting the no-swim order.”

While the strain — O157— isn’t currently being detected, Beaudoin said the community shouldn’t let its guard down.

“We need to be very vigilant about watching those numbers, and if those numbers go above a certain threshold, we need to put up signs and warn people."

E. coli O157 is a toxic strain that can lead to kidney failure, especially in children. Some of the children who got sick this summer were hospitalized and did develop signs of kidney failure, and families are considering legal action.

How we got here

On June 30, the City of Chico issued a press release advising residents to avoid swimming in Sycamore Pool at One Mile Recreation Area in Bidwell Park due to high levels of bacteria in the water.

The advisory came after community reports of children getting sick after swimming in the pool.

Then, on July 18, public health extended the advisory to include all of Big Chico Creek after receiving a total of five infection reports connected to E. coli O157.

On Aug. 13, public health received samples back from the Centers for Disease Control and Prevention (CDC) that confirmed the presence of E. coli O157 at multiple locations in the creek.

What caused the outbreak is still a mystery  

Beaudoin said the agency still hasn’t found the source of the outbreak.

Though still a mystery, Beaudoin said the evidence points to the source coming from animals, not humans. Rumors had circulated throughout the community that unhoused residents living in Bidwell Park were to blame for the outbreak.

Most outbreaks are linked to cattle in some way, Beaudoin said.

“There aren't any cows that are in proximity to Big Chico Creek, at least during this kind of timeframe when the outbreak happened,” he said. “However, birds are able to pass it from the cow to the water. So we had tested a couple different flocks of geese.”

All the geese that were tested were negative. As part of the agency’s investigation with the CDC, other types of animals were also tested for the bacteria. Most recently, deer, which were also negative.

Some have speculated that the bacteria could be coming from goats, which the City uses to clear out brush and reduce fire risk in the park.

While Beaudoin said the agency hasn’t tested goats, he said there haven’t been reports of goats wading into the water, which makes him pretty confident that’s not the source.

“I think what most people would tell you is that this is spread by some sort of migratory bird. Now, maybe that migratory bird lost the E. coli and it won't be a problem next summer, but maybe it didn't,” he said.

It’s this uncertainty that makes Beaudoin believe the strain could be found in the creek again.

“What I’m most nervous about is could whatever brought this variant of E. coli to Big Chico Creek in the first place – could it potentially be migratory, could it come back next summer?,” he said.

He said one thing is for certain, though.

“Even though we're not going out and actively investigating anymore, we're definitely changed here at the health department,” Beaudoin said. “We're definitely more suspicious about this, and really want to keep an eye on things.”

Beaudoin said his team plans to do that by continuing to work closely with city and state officials to get a better understanding of water safety in the long term. He said this could include changing the way the creek is tested.