The number of Lothian hospital wards shut down because of the winter vomiting bug has risen to 12.
Visitors have been told to stay away from a dozen wards and parts of two wards at the Royal Infirmary, where 96 patients and 26 staff have been diagnosed or are displaying symptoms of norovirus.
Among the affected hospitals are the Western General and St John’s Hospital in Livingston, while a dementia ward at Ferryfield House has also been closed.
Figures show the number of cases across Scotland has soared this year. Statistics from Health Protection Scotland show 2016 laboratory reports so far this season – a rise of 46 per cent on 2011 figures.
Norovirus is the most common stomach bug in the UK, affecting people of all ages.
It is infectious and outbreaks spread quickly around closed communities, such as hospitals and nursing homes.
Symptoms come on suddenly and last between 12 and 60 hours.
Dr Alison McCallum, director of public health and health policy at NHS Lothian, said: “There has been a significant increase in the number of cases of norovirus over the past two months and levels across Scotland are higher than in previous years.
“We have strict infection control procedures in place to contain any outbreaks within our hospitals but visitors can make a big difference by washing their hands and not to coming into hospital if they are feeling unwell.”
Edinburgh City Council confirmed an adult at a special school had contracted the virus, while in West Lothian a number of care homes have been closed to visitors.
Last week, 119 pupils at Mauricewood Primary in Penicuik were off school having been struck down with the illness.
Dr John Cowden, a consultant epidemiologist at Health Protection Scotland, said: “One of the problems with norovirus is people vomit rather dramatically who will not have been ill beforehand.
“Then it can become airborne and once that happens, it becomes very difficult to control.”
Mr Cowden stressed he could not confirm the reason for the increase in cases, but added: “Sometimes a new type of norovirus emerges so people who were immune to norovirus are at risk.
“In that situation we’d expect to see more cases.”