Wards have closed to new patients at the Lister Hospital after an outbreak of Norovirus – with bosses admitting services are severely stretched.

The East and North Herts NHS Trust are blaming visitors for bringing the virus in to the hospital.

The trust said friends and relatives are “unaware” of or “ignoring” advice about the winter vomiting bug. Affected areas being closed to new admissions.

People with the virus or symptoms – which are vomiting and diarrhoea – need to be symptom-free for 72 hours before visiting hospital.

The trust’s director of nursing, Angela Thompson, said: “Infection outbreaks caused by this virus can happen very easily when an infected person with symptoms visits somewhere like the Lister.

“Already this year, we have had three wards affected and we’re appealing to the public to help us protect our patients, their relatives and our staff from this highly infectious virus.

“Whilst we understand the desire of people to visit their friends and relatives, we need to remind them that if they have this illness themselves they must not come in to hospital unless at least three days have passed since their last symptoms.

“Children under the age of 12 should not come along on visits at all as they are more prone to picking up and spreading Norovirus infections.

“With three ward areas now affected, we are no longer able to admit new patients to beds in these facilities until the outbreaks are over.

“This causes our staff significant problems that could have been avoided at a time when our services are very stretched already.

“We’re also reminding everyone – patients, their visitors and our staff – to ensure they maintain excellent hand hygiene at all times.

“This includes being extra vigilant about washing hands before and after every visit, using the handwashing facilities provided.”

The trust is also asking anyone who has a procedure or appointment date at one of their hospitals coming up who begins to feel unwell to ring first before attending.

Signs and symptoms of the virus include nausea, vomiting, diarrhoea and giddiness.

The incubation period is 24 to 48 hours, with symptoms usually lasting one to two days.