A second ward has been closed at Altnagelin Hospital in Londonderry due to an outbreak of vomiting and diarrhoea.
Six patients have fallen ill so far, promoting the closure of the 'Gynae Ward 4'.
It has now been shut to admissions after the Trust saw an "increase in vomiting and diarrhoea experienced among patients".
Last week several bouts of sickness led to the Trust closing Ward 8 to new admissions.
Geraldine McKay of the Western Trust said "advice and increased infection control measures" had been taken.
It has since reopened.
On Monday Alan McKinney of the Western Trust said there was "no direct relation between the closure" of the two wards".
"When an increase in vomiting and diarrhoea is experienced in the community it can have an impact on hospital services and instances such as this are often the case at this time of year," he said.
"The Trust's Infection Prevention and Control team is continuing to provide advice and increased infection control measures have been taken.
"No other area of the hospital is currently affected, including any other appointments or services being cancelled."
The Western Trust has also asked the public not to visit patients at the hospital if they have been feeling unwell.