The number of confirmed and suspected cases of the potentially deadly Legionnaires' disease is set to rise, the Scottish Health Secretary has said.
There are 21 confirmed cases of the disease and 19 people are suspected of having the illness but no more fatalities have occurred since Tuesday when one man died, Nicola Sturgeon said.
Of the 21 confirmed cases, 12 are being treated in intensive care, two have been discharged, one has died and the others are either being treated in hospital or in the community.
NHS Lothian said the patient who died was in his 50s and had other health conditions. He was being treated at Edinburgh Royal Infirmary.
The cases are linked geographically to the Dalry, Gorgie and Saughton areas of south-west Edinburgh.
The number of cases is expected to continue rising until the weekend because it can take as long as two weeks for symptoms to show.
Ms Sturgeon said: "This is the most significant Legionnaires' outbreak we have had in Scotland for a long, long time, perhaps since the early 1980s.
"It's a significant outbreak and it's the cause of understandable concern, but it's also resulting in all of the relevant agencies working together very closely, both to manage the outbreak and ensure that patients have the right treatment, and to identify the source as quickly as possible."
Ms Sturgeon said: "What we can say is that no link has been identified between these patients other than a general association with the affected area in the south-west of Edinburgh. What that does is underline the view that the source of this infection is an outdoor community source and not an indoor-specific source, such as would be the case if it was a spa in a hotel. That points, as we have been saying, to cooling towers in the south-west of Edinburgh."
Work around the towers is being led by the city council and the Health and Safety Executive.