Captain William Porterfield confirmed several players were unwell but insisted the outbreak did not spell the end to Irish hopes of reaching the Super Eights stage in Sri Lanka.
"A few lads have gone down with upset stomachs," Porterfield said. "As long as everyone wakes up well tomorrow (Monday) morning hopefully we'll have a full squad to pick from."
Ireland were continuing to plot their game plan for the Group B clash in Colombo, when both sides will be looking to recover from opening defeats by Australia.
With the likes of big-hitting opener Chris Gayle so potentially dangerous, Porterfield acknowledges the importance of Ireland getting off to a good start.
Gayle cracked a rapid half-century in the loss to Australia, which came by the Duckworth-Lewis method after rain brought an early end to play.
"They can be very destructive but they've got the capability of getting out as well," Porterfield said. "So we'll be looking to put pressure on them and the first six overs with bat and ball are going to be a crucial part of the game.
"If you can restrict them in those first six overs and obviously pick up a few wickets and get a bit of a start ourselves that'll be key to the game really."
Batsman Niall O'Brien is convinced Ireland, coached by former West Indies batsman Phil Simmons, will forget about any lingering sickness once the match gets under way. He said: "It's not ideal whatsoever but it's happened before.
"From a personal point of view I've been sick (in the past) and you sometimes find a bit of resolve, and that's something Phil will be trying to stress on the players who are sick. But it's a Twenty20 and there's a lot of adrenaline, so hopefully they will overcome any illness in the camp."