More than 20 people have contracted COVID-19 in a vascular ward at Ayr Hospital, it is understood.
The area underwent a deep clean and patients with the virus have been sent to a dedicated COVID-19 ward.
NHS Ayrshire & Arran have confirmed that patients and staff tested positive.
Dr Crawford McGuffie, Medical Director, said: “NHS Ayrshire & Arran can confirm that a number of cases connected to a ward in University Hospital Ayr have tested positive for COVID-19.
"Affected staff, patients and their families have been informed.
"Patients who tested positive for COVID-19 have been transferred to a dedicated COVID-19 ward and continue to be cared for with the appropriate infection control measures in place including enhanced environmental disinfection.
“Staff who have tested positive have been excluded from duty and told to isolate at home in line with national Test and Protect requirements.
"A programme of screening asymptomatic patients and staff is in place.”
A political source who revealed the outbreak to the Local Democracy Reporting Service said staff are “under so much pressure” and some are at “breaking point".
The source said about 22 people may have been infected following the incident.
Hospitals in Ayrshire were caring for 107 patients with coronavirus yesterday (November 26).
There were fewer than five infected people being treated in ICU yesterday but that number reached 10 earlier this month.
Dr McGuffie said the ward outbreak was reported to Antimicrobial Resistance and Healthcare Associated Infection Scotland.
He added: “We appreciate this is a very worrying time. However, we would like to assure members of the public that every measure is being taken to protect patients and staff.”
The health board wants to remind people of the symptoms of coronavirus.
They are: new persistent cough, high temperature; and or loss of taste and smell.
Anyone with symptoms should book a test and self-isolate immediately.
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