Half of St. Mary’s General Hospital’s fifth floor is closed to visitors and new patients following an outbreak of a gastrointestinal illness.

Hospital officials announced the outbreak Monday, saying five patients and four staff members in the general medicine unit have illnesses with symptoms including nausea, vomiting or diarrhea.

It’s not known if the illnesses are connected.

Visitors to the unit are asked to ensure patients only have one visitor at a time, all of whom report to a nearby nursing station and frequently clean their hands.

Outside food and drink is also prohibited in the unit.

Patients who would normally be admitted to the affected area are being taken elsewhere, hospital officials say.

Infection control procedures are in place.