Around 80 hospital staff and patients in north Wales are being offered anti-flu drugs as a precaution against avian flu.
The National Public Health Service for Wales said 79 people from a ward at Ysbytly Glan Clwyd had been offered tamiflu following possible contact with a health worker confirmed as being infected with the H7 flu virus.
A further 69 patients and staff from the A&E unit and two wards at Ysbyty Gwynedd in Bangor are also being contacted because another confirmed case was recently a patient there.
The NPHS stated that none of the 12 cases of avian flu identified so far were seriously ill and that the risk to the general public was assessed to be low. The source of the outbreak is a smallholding near Corwen.
Marion Lyons, lead consultant in communicable disease control for the NPHS, said: Â'Experience of this particular bird flu virus (H7N2) in humans is limited so we are actively managing the public health response.Â'