The reality star said there are “no exceptions” to who can catch the illness and his diagnosis shows it can be “caught by anyone”.
Collard said the friend he travelled with has tested negative, as have other people at his gym.
Writing on his Instagram story, he wrote: “A hell of a lot of people DMing me asking what this is like and where it’s from etc.
“First point, my best mate and me shared a bed/flight for 4 days together in Greece and he’s Negative and I’m Positive. So it could be from anywhere.
“Done 50+ tests in gym and all negative.
“Secondly it obviously can be caught by anyone since I’d like to think I’m fitter & healthier than the average joe. No exceptions.
“Third: How bad is it people keep messaging. For me, it’s actually ok, manageable. Best way to describe it is like a bad hangover with a mega dry throat.
“Annoying more than anything and it comes in waves. Wanted to do work and a bit (of) easy training yesterday but today feeling a bit fuzzy in the old head.
“Hope that answers a few.”
On Monday Collard shared his workout routine, saying he would continue to exercise in spite of Covid-19.
He wrote: “Mondays. Set the tone. Before anyone gets on the high horse. I know my body. I know my limits. I know what makes me feel good mentally & physically.
“My body doesn’t work well with lying watching Netflix, actually my backs killing from too much of that on day 3 already. My body’s primed for action. Corona or no corona. Be better.”
Reporting by Press Association