Visitors to Babington Hospital are being urged to help prevent an outbreak of a winter vomiting bug by staying away if they show symptoms.
Officials at Derbyshire Community Health Services Trust warned Norovirus could seriously affect vulnerable patients at the Derby Road institution.
Statistics show there have been three outbreaks of the virus at the trust this year, the latest being in September.
The last major outbreak in Belper was in Janury 2011, when patients had to be diverted to Heanor Memorial Hospital.
Symptoms of Norovirus include diarrhoea and vomiting and, just like flu, the virus can be exacerbated by colder weather, and can be particularly serious for people who are already ill or who have a long term condition.
The bug is described as being highly contagious and can spread rapidly anywhere that people are gathered, such as schools, offices or hospitals.
Michelle O’Connor, Senior Matron in Infection Prevention and Control for Derbyshire Community Health Services NHS Trust, said: “We’re asking people to think carefully before visiting hospitals if they or anyone in their family has even mild symptoms of stomach upset.
“We know that sometimes visitors feel they must take every opportunity to visit sick friends or relatives.
“However, if they themselves have been unwell, they could be putting others at risk.
“If visitors are unsure whether they should come in or not they can always ring the ward first to get some advice.”
Although people usually recover without treatment in 24 to 72 hours, it is important to stay away from work, school, college or any social gatherings for at least 48 hours after symptoms of Norovirus disappear.
They are also urged not to visit their GP surgery or the A&E Unit at the Royal Derby Hospital.
Sufferers should recover naturally by ensuring they get plenty of rest and avoid dehydration with lots of non-caffeinated drinks.
One of the most effective ways of preventing the spread of infections is regular hand-washing with soap and water.
There are many types of Norovirus, and it is possible for infection to occur several times.