The highly infectious norovirus has struck at Watford General Hospital.
After months of bucking the national trend by keeping the superbug at bay - with just one case of infection since the summer - West Herts NHS Hospitals Trust has succumbed to the germ.
Medical director at the trust, which also runs Hemel Hempstead’s Urgent Care Centre and St Albans City Hospital, Dr Colin Johnston said: “A small number of cases have been confirmed on Sarratt and Croxley wards at Watford General Hospital.
“We are asking visitors to help us by not visiting these two affected wards unless it is essential. Visitors who do need to attend should telephone before arriving.”
Anyone planning to visit patients is asked not to bring children and to stay away if ill. Those who have suffered with sickness or diarrhoea should be clear of symptoms for 72 hours before visiting.