England won a Six Nations match in Dublin for the first time in 10 years, beating a lacklustre Irish side who struggled with basic handling errors and injury disruption..
Ireland face an anxious wait on the fitness of key men across the field, including flyhalf Jonathan Sexton, centre Brian O'Driscoll, fullback Rob Kearney and three members of their starting pack.
"It is absolutely a substantial list but we've always tried to state yes, that's the injury list but we work on because there's an opportunity for someone else and that's all we can do," Irish head coach Declan Kidney said.
Zebo was forced off with a broken foot which will rule him out for up to 10 weeks.
Sexton, who also limped off in the first half, is due to undergo a scan on a potential hamstring tear that would cut short his championship, and forwards Sean O'Brien, Mike McCarthy and Donnacha Ryan all suffered knocks.
"About a week ago we had major concerns...this time it does look way more serious but it's an uncontrollable," said Kidney.
In the back line, Kearney picked up a dead leg and O'Driscoll, who limped through much of the match, sustained an ankle injury.
It was busy day for O'Driscoll, who rushed to hospital on Sunday morning to be with his wife for the birth for their first child, a baby daughter named Sadie, just hours before kickoff.
Kidney said there was a still a "hell of a lot to play for" despite the defeat that left England as the only team capable of winning a grand slam.
"The Grand Slam is a wonderful thing to win but trying to put it together take an awful lot, there's a championship first and foremost to play for and we're well in that," he said.
Those comments were echoed by Kearney who said England were deserved winners on the day, but that Ireland still had a strong chance of claiming the championship.
"This competition is wide open and I think the days of grand slam are going to be difficult. I don't think we'll be seeing too many of them," Kearney said.
"We have one win and one defeat...we have to realise that we are still hugely in the hunt," he said.
Ireland were already without injured first-team regulars Paul O'Connell, Stephen Ferris and Tommy Bowe.