It can lurk in water, on unwashed fruits and vegetables, and uncooked meat.
But E. Coli also lives in our stomachs.
Most of the time E. Coli is harmless, but some strains can cause deadly complications.
This is the story of one little girl who lost her life as a result of one of them.
That little girl's parents have more questions than answers as they mourn the loss of their daughter.
8% of children that get E. Coli O157:H7 one of the most dangerous strains, also develop HUS, a sometimes-fatal secondary illness that causes, among other problems, kidney failure.
This 8-year-old was part of that minority and her parents still don't know why.
Her name was Evie Hope Wray, a soccer and cat-loving second-grader at Lutie Elementary School in Theodosia.
Her mom is the principal there, dad runs the family farm.
Her older brother JD never ran anywhere without Evie.
“She’s just a fun-loving kid, always looking for adventure, with her brother all the time,” explains Evie’s mom Nancy Wray.
When this close-knit family's youngest daughter became horribly ill, it was devastating.
“Her vitals started dropping… they hooked her up to oxygen and when that didn’t work, they had her on all kinds of drips,” Evie’s dad Tom Wray remembers.
She was diagnosed with a serious strain of E. Coli, but it was HUS that caused her death.
With no way to treat the infection, doctors could merely provide dialysis to support her failing kidneys and sedatives to reduce her pain.
“She was on about seven different machines. I just touched her and said, ‘momma’s here.’”
Evie passed away at a Columbia hospital, surrounded by people who loved her.
But those people are still haunted by how- how did this happen?
“We’re searching, we want to know what happened to our daughter,” the couple pleads.
“What we’re able to do is limited when you have one case. You look for a source but it’s difficult to come to a conclusion.”
That’s nurse Susan Shipley with the Ozark County Health Department.
She says they haven’t seen a case of O157:H7 in four years.
It's rare and hard to trace.
The Wrays tested their well water, which often contains harmless strains of E. Coli, but it came back completely clean.
Thursday was big brother JD's first day back at school, and mom and dad say he talked about Evie.
They may not know why she's gone, but they know where she went- to a better place.
There aren't many E. Coli symptoms.
Excessive diarrhea, especially bloody diarrhea and sometimes fever can be signs of E. Coli.
Nancy says if she has any advice to give to other parents, it's make sure your children wash their hands.
That's the best way to stop the problem before it hurts your family.