More than fifty patients and staff have become ill with the winter vomiting bug at the Dumfries and Galloway Royal Infirmary.
Three wards remain closed, after the outbreak was confirmed on Friday.
Infection control procedures are in place.
Visitors are being asked to stay away, if they have any symptoms.
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The historic event always takes place on the last Friday in July.
Early enquiries suggest the men may have taken the drug Blue Valium. Two of them remain in hospital with breathing problems.
More than 8,000 people are expected to attend over the three day event, which starts at 7pm tonight.