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:
More top news
Carlisle have secured their Football League status by beating Plymouth Argyle 2-0 at Brunton Park.
Kerrie brings you Saturday night's forecast
Carlisle are preparing for game that could see them safe from relegation. They welcome Plymouth Argyle to Brunton Park for a 3pm kick-off.