The 22-year-old tested negative when the first round of testing was conducted last week but returned a positive test just three days later at the second time of asking.
Six players and staff from three Premier League clubs tested positive for the virus when the first tests were done on May 19 including Watford’s Adrian Mariappa and Burnley assistant manager Ian Woan.
Two players were found to be infected with the virus from the second round of tests, with Ramsdale coming from Bournemouth and another player from an unnamed Premier League side.
Ramsdale has been left shocked by the development and he will now be required to go into self-isolation for seven days.
"I've been trying to figure it out for the past two days," Ramsdale told The Sun. "My test last Monday before we started training was negative.
"So this last week, I've done the usual things like going to the supermarket and going to the petrol station to fill my car.
"Once you've contracted the virus, it shows in your blood.
"That was obviously not the case [after the first test] and it's been the three days between the two tests when I've contracted the virus.
"I've been just as careful as before on lockdown and it seems to be a shopping trip where I've caught it."
Ramsdale was in goal for all but one of Bournemouth’s 28 league games before the season was put on hold.
