Allardyce confirmed that the virus had broken out within the camp prior to the weekend's Barclays Premier League match against Chelsea, but refused to name the individuals.

Asked whether Chris Samba and David Dunn were two of the sufferers, Allardyce said: "It's definitely swine flu - you've speculated on the names and I'll leave it at that.

"We have had one more case this morning, one more player and there are a couple of staff.

"Other than that, the others that we left behind are recovering well but not available for tomorrow."

Allardyce said Blackburn had only decided to play the fixture at Stamford Bridge - which they lost 5-0 - because they were bound to do so by Premier League rules, and admitted there was a chance the virus could have been passed on.

"The Premier League has tried to sit on the fence by saying that we didn't request to have the game called off," Allardyce said.

"We knew we couldn't get the game called off because we were told way back in February or March when we took some guidelines that unless there was some government legislation, everybody had to do whatever they had to do.

"If there was a swine flu outbreak, you couldn't call a game off, no matter what.

"We fulfilled our total, 100 per cent, responsibility by confirming two cases of swine flu and suggesting that it looks like one or two other players and members of staff had similar symptoms, and we made the same phone call to Chelsea."

Asked about the danger of it spreading on a match day, Allardyce said: "It's a highly contagious strain as everybody knows but I can't comment any further than that."

Allardyce revealed that a number of the squad felt unwell on Saturday but played regardless.

"We just got on with it and put all the players we could together," he said.

"We left about six players back here on stand-by, just in case a few more of the lads went down with symptoms on the Saturday morning - so we could get them on a train for the late kick-off.

"All those lads that were not quite 100% said that they wanted to play and go out and do the best they could - and they did, so full marks to them.

"We suffered a heavy defeat. It is still no excuse for a 5-0 - but it didn't help."

A spokesperson for the Premier League confirmed Blackburn made contact with them before the Chelsea match but that no postponement was requested - adding that if one had been, the club would have been asked to prove they did not have enough players available to play the fixture.

As for his own health, Allardyce joked that the loss as Stamford Bridge was always going to leave him feeling low.

"I'm not too sure if it's the downside of getting beaten 5-0 or it's the symptoms of swine flu, but I've been pretty miserable the last few days - I know that," he said.

"I wouldn't say I've been feeling my best but I'm not sure if that's not down to the performance of the players."

Despite the problems facing his squad, Allardyce remains confident about the team he intends to put out against Peterborough and their chances of advancing to the quarter-finals.

"If we don't have too many more players go down with it, we've got a very good side for tomorrow," he said.

"We were going to make some changes to the side anyway - but certainly we will be forced into those changes now.

"There will be a few players that were 100% on Saturday playing again, and a few players who haven't played as much in the first team who are also 100% who will be selected for the side against Peterborough."

Pascal Chimbonda (calf) and Vince Grella (thigh) will miss out through injury, but Allardyce hopes the pair will be available for the weekend trip to Manchester United.

A statement from the Premier League read: "As ever, when it comes to health matters the Premier League will be guided by the relevant statutory authorities.

"If a club postpones any of their matches they would have to prove that they were unable to fulfil their fixture, however we do not anticipate, at this stage, any circumstances under which a match could be justifiably postponed."