The number of people affected by the norovirus outbreak at the Glasgow 2014 Athletes' Village has risen to 48.
Health officials said 18 security staff reported unable to work yesterday due to symptoms of the virus which causes sickness and diarrhoea.
No athletes or team officials have been taken ill so far.
A temporary toilet facility has been shut at the village in Glasgow's east end where athletes began arriving this week.
The Commonwealth Games opening ceremony takes place on Wednesday at Celtic Park.
NHS Greater Glasgow and Clyde said "every precaution is being taken and everyone is being very vigilant".
Public health consultant, Dr Gillian Penrice, said: "Village residents and workforce have been informed and issued with health information.
"There have been no reports from athletes or team officials and the Village is open and operating as normal.
"We continue to monitor the situation closely."
Norovirus is the most common stomach bug in the UK, affecting between 600,000 and one million people of all ages every year. Symptoms are usually mild and generally last for 24 hours.
Up to now 32 workers were reported to be affected by norovirus but two cases have been discounted. Everyone with symptoms is being advised to stay at home until they have been clear for 48 hours.
First Minister Alex Salmond said earlier that Games organisers were confident they had identified the probable source of the outbreak, a temporary facility in use during construction work in the security area.