Fears have been raised that swine flu is circulating in Edinburgh after two students tested positive for the disease but have not been in contact with any known cases or travelled to the United States or Mexico.

The two students, a 20-year-old man and a 21-year-old man from Greece, who both study in Edinburgh, developed symptoms of the disease last Sunday while in Scotland.

They were tested in Greece and found to be positive for H1N1 swine flu but they have not travelled to countries where the disease is widespread and to their knowledge have not been in contact with anyone confirmed or suspected of having the disease.

The cases could mark a significant shift in the swine flu outbreak in Scotland as doctors in Greece have questioned whether the virus is spreading more widely but current testing methods are not detecting it.

A spokesman for Heriot Watt University, where the two students are studying, said: “There were seven potential contacts who have all been cleared. We are continuing to operate as normal and we are in close contact with the relevant health and governmental bodies who are monitoring the situation.”