A total of 11 prisoners have tested positive for coronavirus and more than 80 are self-isolating, the Scottish Prison Service has said.
The latest figures show 85 inmates are self-isolating across 12 prisons, with more than 40 of those in Addiewell, West Lothian, after a hall was closed down on a precautionary basis following positive tests.
Since the start of the outbreak, two deaths in Scotland's prisons have been linked to the virus.
Francis McCarthy, 59, died on Monday April 13 after being taken to hospital from HMP Low Moss with suspected coronavirus.
He was sentenced to life after being convicted in 1985 of murdering 26-year-old Thomas McKirdy from Paisley.
The previous week, serial sex offender John Angus, 66, who was being held at HMP Edinburgh, became the first Scottish prisoner to die after contracting the virus.
A spokesman for the prison service said those self-isolating include prisoners with symptoms and those who share a cell with them or have been in close proximity to them.
In a statement on its website, the prison service said: "The safety and well-being of those living and working in our prisons is a priority for the Scottish Prison Service (SPS).
"We are working with the Scottish Government, Health Protection Scotland, our NHS colleagues and a range of other partners on a daily basis to manage the unprecedented challenges we are all now facing.
"The SPS has robust pandemic plans in place, which are implemented on a phased basis in response to escalation demands.
"We continue to follow the advice from the chief medical officer, which means that anyone in our care who displays symptoms of the virus will be asked to self-isolate, as well as those how may have been in contact with that individual."
