Norovirus symptoms include a sudden onset of vomiting - which can be projectile in nature - and/or diarrhoea - which may be profuse and watery.
Some people may also have a temperature, headache and stomach cramps. The illness usually completely resolves in one or two days and there are no long term effects.
For most people affected by norovirus it is an unpleasant but short lived illness.
There is no specific treatment other than to let the illness run its course, taking plenty of drinks to replace lost fluids.
More top news
A toddler was in need of an unusual rescue after she got a kettle stuck on her head while playing at home in Chile.
British Defence Secretary Michael Fallon is in the Middle East to gather support for the international military campaign against IS.
Beware! The super-sized spiders are coming. And they seem to be everywhere! But why? A warning - this story is not for the faint hearted!