‘Hundreds’ of holidaymakers have been struck down by a sickness bug on a once-in-a-lifetime cruise to see Up Helly Aa. Fred Olsen’s Balmoral ship was hit by a suspected gastroenteritis outbreak as it was due to dock in Lerwick for Shetland’s annual fire festival on Tuesday. Gastroenteritis is a common condition usually caused by a bacterial or viral bug, and results in diarrhoea and vomiting. Virus made cruise ‘unpleasant’Julie Homer said it was an “unpleasant environment,” despite Fred Olsen staff “working hard” to contain the bug. She said: “We had two rough sea days, after the virus outbreak was announced last Thursday.