The Premier League is facing its first outbreak of swine flu after Blackburn Rovers confirmed three of their players and two of their backroom staff have contracted the illness.

Tomorrow's Carling Cup tie against Peterborough United will go ahead despite Allardyce expressing fears that the bug may have been passed on to more players.

Chris Samba and David Dunn were ruled out of the 5-0 defeat by Chelsea at Stamford Bridge on Saturday, due to what Sam Allardyce described as a virus. This afternoon a third, as yet unnamed, member of the squad and two members of staff have been diagnosed with the illness. It is understood that one of those to contract swine flu is the club doctor.

"It's definitely swine flu - you've speculated on the names and I'll leave it at that," Allardyce, the Blackburn manager, said. "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 are not available for tomorrow."

Allardyce said Blackburn had only played Saturday's match at Stamford Bridge 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 to players from Chelsea, Allardyce added: "It's a highly contagious strain as everybody knows but I can't comment any further than that."

Allardyce had earlier confirmed Dunn and Samba had contracted a virus. "David Dunn and Chris Samba have a virus and a couple of the other lads who were playing against Chelsea have that virus or we think they are coming down with it," Allardyce added.

"We will hopefully get them back next week when we have to go to Old Trafford. But it is one of those viruses that can see you out for up to six days so we'll have to see."

Most clubs have taken precautions to limit the spread of the bug, but overall national figures suggest a spike in the number of cases in recent weeks.