The reigning Olympic, world and Commonwealth 100m and 200m backstroke champion said she was devastated to miss the events where she was red-hot favourite."I am gutted to medically withdraw," said the 24-year-old, widely considered the greatest backstroker of all time."What I thought a few months ago was the flu has turned out to be my body fighting glandular fever."I was sick going into trials and I just have not got better and I am worried about pushing myself so hard that I end up with chronic fatigue."It was a hard decision to make but it was the right one."Swimming Australia head coach Rohan Taylor said McKeown's health must be the priority."We all know how fierce and competitive she is -– and she showed that by performing the way she did at trials," he said. "Kaylee is a once in a generation athlete. She is what we call a racer. "We are going to miss her on team not just in the pool but out of the pool with her experience and leadership but I personally feel, respect and support her decision to prioritise health."Australia will now take a 59-strong swim team to the Commonwealth Games in Glasgow from July 23-August 2 and 43 to the PanPacs in Irvine, California from August 12-15.