The devastating superbug Norovirus has broken out in Cornwall.
The outbreak has hit a nursery and care home and three wards at the Royal Cornwall Hospital.
The easily transmitted virus causes vomiting and diarrhoea in those affected.
A spokesman for NHS Kernow said: “Norovirus has been reported in Cornwall this week with bay closures in three wards at Royal Cornwall Hospital and cases reported in a care home and a nursery.”
Because of the ease with which the virus can be spread, health bosses warned patients with symptoms should not visit their GP unless symptoms persist for more than 24 hours.
Those suffering from vomiting and diarrhoea should not visit anyone in a hospital or care home and should stay away from work or school until they have been free of symptoms for 48 hours.
It is not yet known which nursery and care home have been affected.
It is estimated that Norovirus affects between 600,000 and a million people in the UK each year. Outbreaks can affect more than half of susceptible people and usually tend to affect people who are in environments such as hospitals, nursing homes and schools
NHS Kernow said most people make a full recovery within one to two days but some people, usually the young or the elderly, may become very dehydrated and require hospital treatment.