Sixty patients and staff are believed to be experiencing symptoms of the vomiting bug in Sligo University Hospital.
Eight beds are closed and there are 20 patients with a confirmed diagnosis in what has been described as an unprecedented outbreak of the norovirus in the experience of Sligo University Hospital.
Management is appealing to people not to come to the hospital unless absolutely necessary saying that people with family members in critical situations will be facilitated but otherwise ward restrictions are in place, with no children allowed because they would be particularly susceptible to the illness.
Management is also encouraging the public to contact their GP or GP out-of-hours service in the first instance and not to attend the emergency department unless absolutely necessary.
Patients with pre-planned hospital appointments such as outpatients who have not had any symptoms of vomiting or diarrhoea should attend their appointment as normal, unless otherwise advised by the hospital.
Sligo University Hospital emergency medicine consultant Dr Fergal Hickey was speaking on Shannonside's Let's Talk programme.