When doctors told Ali Jardine they may have to amputate her leg, she thought she would never walk again.
The 51-year-old from Girrawheen says she is lucky to be alive after a spider that was hiding in her sock bit her on her right ankle at her Duncraig home in 2010.
Ms Jardine initially ignored the bite because it appeared to heal and she had no symptoms. But she collapsed two weeks later and doctors told her she had acute blood poisoning.
She spent several weeks in Sir Charles Gairdner Hospital, twice had surgery on her leg and was in a wheelchair or on crutches for almost eight months.
When doctors spoke to her about the possibility of amputating her leg, she refused.
Now she can boast having climbed Ben Nevis, the highest peak in Britain, alone to prove to herself she had made a full recovery and anything was possible.
Ms Jardine travelled throughout Britain and Greece over the past few months and returned to Perth last week to carry on in her new job as a personal trainer. She will soon release a book about her experiences.
She said she did the climb in June as a personal challenge but she hoped to climb other famous peaks for charity.
"When I was on the top of Ben Nevis I cried . . . I was so happy to be alive," Ms Jardine said. "I didn't care how long it was going to take me, I just wanted to do it.
"The day I climbed it was a beautiful sunny day and I just sang as I went. I felt on top of the world."
Ms Jardine said doctors told her that if not for her positive attitude and high level of fitness she probably would not have survived.
"I had acute blood poisoning, I was on antibiotic drips . . . I'm very lucky," she said. "I'm just so happy I've still got my leg because it was touch and go that they were going to take it off.
"I walk for miles and miles and miles here in Australia because I feel so lucky."
The spider that bit her was never identified, but doctors believe it was a white-tailed spider.
Ms Jardine said she had made it her mission to encourage others to live healthily and stay positive.