Mark Cueto has become the latest England player to be struck down with a stomach bug.
The Sale winger has not been ruled out of Saturday's RBS 6 Nations game against Ireland but he did not train with the squad today.
Northampton's Chris Ashton joined the squad at their Pennyhill Park base today as a precaution.
England captain Steve Borthwick, Simon Shaw, Toby Flood and Shontayne Hape have all suffered from stomach upsets during the championship.
Hape is the only player to have missed a game through illness, having withdrawn from the bench on the morning of England's 30-17 victory over Wales.
If Cueto is ruled out it will leave manager Martin Johnson with a selection headache for the Ireland game.
Ashton is uncapped while Ben Foden, England's back three replacement, is not a natural winger.
Mathew Tait is another wing option but moving him from outside centre would force Johnson to reshuffle his back line.