Thirty patients and three members of staff are believed to have contracted the norovirus.
Hospital managers are now urging people to take all the usual measures to stop the problem from getting worse.
Infection Control Manager Elaine Ross explains more:
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John Davidson, who grew up in Newcastleton, was killed while trying to arrest a suspect last week.
Police are looking at CCTV footage after money was taken from her bag in a shop in the town.