Rumors continue to circulate that unhoused residents living in Bidwell Park are to blame for the E. coli O157 outbreak in Big Chico Creek. But Butte County Public Health maintains that’s unlikely.
Health Officer Dr. Jarett Beaudoin said he’s been hearing a lot of concerns from residents about the source of the bacteria and addressed them in a video today.
“The most common question I get when I’m talking to people is, ‘how do we know that this isn’t due to homeless people living in the park?’” Beaudoin said.
An investigation is ongoing. Beaudoin said no possibilities have been ruled out, but the evidence so far doesn’t point to humans.
5 reasons why officials say people likely aren’t the cause
- Upstream detections: The bacteria has been found as far upstream as the Five Mile Recreation Area. Beaudoin said that most unhoused residents live downstream, so the way it’s showing up in the creek points to another source.
- How long it lasts in people: People don’t carry E. coli O157 for very long, usually only about two weeks. Beaudoin said public health has confirmed the bacteria has been in the creek since at least June, which is beyond the time a single infection would last.
- No local cases among homeless residents: Public Health has received no reports of unhoused people who live in or around the park getting sick with E. coli O157. With this strain, Beaudoin said an infected person would likely go to a doctor or the hospital, and his department would be notified.
- More bacteria than a few people could cause: The levels of E. coli found in multiple parts of the creek would likely require a very large amount of human waste. Beaudoin said it’s a lot more bacteria than a few people could produce.
- E. coli O157 is usually linked to animals: Beaudoin said most outbreaks of this strain of E. coli are caused by livestock and birds, not people.
What about septic tanks?
Beaudoin also addressed questions about whether the outbreak could be tied to leaking septic tanks. He said that’s unlikely, partly because of the short two-week window people carry E. coli O157. But he also pointed to DNA testing.
Beaudoin said public health has done whole genome sequencing, which shows whether two E. coli O157 samples are genetically the same. The strain found in the creek, in sediment and in children who got sick are all identical. If leaking septic systems were responsible, he said, the results would likely show strains that didn’t match.
“E. coli O157 mutates, and so usually it doesn't stay identical. So we know that this is coming from one source,” Beaudoin said.
Next steps
Public Health has tested geese scat for the strain, but it tested negative. Beaudoin said the department will continue to test animals, including deer and other bird species.
The Centers for Disease Control and Prevention initially confirmed the strain in samples taken from Sycamore Pool, the Chico Creek Nature Center, Hooker Oak Park, Five-Mile and Alligator Hole. Now Public Health is working with the Central Valley Regional Water Board to collect additional water samples to determine if E. coli O157 is still present.
In the meantime, Big Chico Creek will likely be closed for the rest of the swimming season.
“We are looking at these areas where we are finding O157, and certainly, if we find new information, we’ll let everyone know,” Beaudoin said. “We have not ruled out anything thus far.”
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