It started two to three days after the team arrived.
This coming weekend of sport is going to be a hectic one but sadly, the last of the three Irish games has been rocked by illness.
According to BBC Sport Northern Ireland, a few members of the Ireland International Rules squad are suffering from a vomiting bug and are currently confined to their Adelaide hotel rooms.
The team's physio, Enda McGinley, confirmed to the BBC that "four or five" of the team members, including himself, have come down with illness.
Ireland's first test with Australia will kick off early on Sunday morning, at 5am, and while there is only a couple of days for the members to recover, McGinley is confident that all players will be fit and ready before the series opener.
"Three or four others along with myself have been affected by one of those problems that is associated with long-haul flights," said the former Tyrone midfielder.
"Around 48, 72 hours after we arrived some of us starting coming down with a bug.
"All the steps are being taken to limit its spread within the camp, because it's obviously far from ideal with the Test match coming up this Sunday.
"Players that are affected have been given single rooms and everybody has individual water bottles, so all the steps that can be taken, are being taken," he said.
Apart from the vomiting and diarrhoea bug, McGinley confirmed that the Irish squad are not carrying any injuries into the first Test and said that he is "very confident that nobody will [have] to sit out at this stage".
Ireland's 23 International Rules squad is as follows:
N Morgan (Tyrone), C Barrett (Mayo), G Brennan (Clare), E Cadogan (Cork), K Clarke (Cavan), P Crowley (Kerry), K Feely (Kildare), P Geaney (Kerry), N Grimley (Armagh), P Hanley (Gold Coast/Mayo), B Harrison (Mayo), C McManus (Monaghan) vice-captain, Michael Murphy (Donegal), N Murphy (Sligo), P Murphy (Kerry), K O'Connell (Monaghan), S Powter (Cork), A O'Shea (Mayo) captain, N Sludden (Tyrone), E Smith (Roscommon), C Sweeney (Tipperary), Z Tuohy (Laois), S Walsh (Galway).
