New South Wales father-of-three Michael Lindquist thought he was coming down with a "simple flu", but three days later he was in hospital in an induced coma.
Unknowingly, the previously fit and healthy 37-year-old from Coffs Harbour had become infected with a flesh-eating bacteria, otherwise known as necrotising fasciitis.
While in hospital, the infection in his leg turned septic and doctors told his wife it was touch-and-go whether he would survive.
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Necrotising fasciitis is generally caused by Strep A, a bacterium found in the throat and on the skin, entering the bloodstream through a cut or break in the skin.
But, in Mr Lindquist's case, doctors are still unsure how it entered his body.
"They still don't know how it happened," Mr Lindquist's wife, Zanna, told 9news.com.au.
"There doctors looked at him and there was nothing that really looked like a big infection site.
"It just came out of the blue and everything happened so fast. That's the thing that really rocked our world."
Mr Lindquist's terrifying health ordeal started about a week-and-a-half ago when he first fell ill with flu-like symptoms.
"On the Saturday, I took my son for a bike ride and I felt like I pulled my groin muscle," Mr Lindquist said.
The next morning, Mr Lindquist felt cold and achey and he and his wife assumed he had the flu.
"I just felt tired and I thought it was just a simple man flu and that I would get over it," Mr Lindquist said.
By the next morning, however, Mr Lindquist's condition had deteriorated rapidly.
"I was so delirious, I couldn't form sentences. It was really strange because my wife was talking to me and I couldn't formulate an answer.
"He was slurring his words and my first thought was, 'Oh my God, he's had a stroke in the middle of the night,'" Mrs Lindquist said.
Alarmed, Mrs Lindquist rushed her husband to the emergency department at Coffs Harbour Base Hospital.
Mr Lindquist had a fever of 40 degrees and was admitted almost immediately, with doctors putting him on antibiotics to treat a suspected infection.
An ultrasound ruled out appendicitis, however a CT scan revealed a build-up of pus in Mr Lindquist's thigh.
With his condition deteriorating rapidly, Mr Lindquist was taken into surgery in the middle of the night to drain the fluid and remove the infected tissue in his leg.
After the surgery, he was put in an induced coma and taken to intensive care.
Mrs Lindquist said she didn't know her husband was going to be put into an induced coma and was shell-shocked by how quickly he went downhill.
"The doctors had to spell it out. They said, 'The next 24 hours are critical. And I said, 'Yes, critical for his recovery. And they said, 'No, the next 24 hours are critical for if he will live or die.'"
"And that was the point where I went, 'Oh my god, hang on. How did we get here?'"
To her relief, Mr Lindquist woke from his coma the next day. He was then airlifted to the Royal Prince Alfred Hospital in Sydney for further surgery.
Doctors were happy with the outcome and Mr Lindquist was flown back to Coffs harbour Hospital on Tuesday, before being discharged yesterday.
Mr Lindquist, who said he liked to keep fit with mountain biking and jiu jitsu, said he never expected to go through such an extreme health scare at his age.
"The moral of the story is that you can't just treat everything like it's a cold," he said.
"You have got to pay attention to what your body is doing, because if it was up to me, I probably would have never gone to the hospital, honestly.
"You just think, I'm 37, I'll just drink some water and I'll be fine."
The father-of-three is now facing a lengthy recovery time.
A close family friend, Carly Mills, has set up an online fundraiser to help the family with ongoing medical costs and other expenses, which she said were expected to be considerable.
"The cut on Michael's leg is all the way from his knee to his groin so it will be a hard physical recovery for him," she said.
"He's self-employed and we are not sure how long he will be out of work for."
Mrs Lindquist, who runs a local pre-school, would also likely need to take time off to care for her husband and children, Mills said.
Mrs Lindquist said she and her husband were both grateful for the outpouring of support they had received from the community.
Contact reporter Emily McPherson at emcpherson@nine.com.au