MSPs are set to be updated on efforts to deal with a deadly outbreak of Legionnaires' disease.
By Wednesday the number of confirmed cases of the disease had risen to 21 - with one person having died.
There were also another 19 people who were suspected of having the illness, which is linked to the south west area of Edinburgh.
Nicola Sturgeon, the Scottish Health Secretary, will give a statement on the outbreak to MSPs at Holyrood.
On Wednesday she described it as "the most significant Legionnaires' outbreak we have had in Scotland for a long, long time, perhaps since the early 1980s".
She said: "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."
The first case of the disease was confirmed last Thursday and since then bosses at NHS Lothian have established an incident management team, chaired by Dr Duncan McCormick, consultant in public health medicine.
The Scottish Government's resilience committee has also been meeting to deal with the outbreak.
All those suffering from the disease have links to the Dalry, Gorgie and Saughton areas in the south west of the Scottish capital. Cooling towers in the area have been identified as the probable source of infection, with 16 towers on four different sites already having been chemically treated.
While the number of cases is expected to continue to rise for several days, Dr McCormick said it was hoped they would start to fall after that. He said: "We are confident we have identified the source and we have taken steps to rectify that. So while we expect to see more cases over the next few days, we would expect after a few days, maybe five or six days, to start to see a decline."
