The colder months are traditionally the harbinger of winter illnesses. Like the flu, for example. But there's one particular virus that's also become synonymous with the season: norovirus. An extremely contagious infection that causes vomiting and diarrhea, this nasty bug can infect people of all ages, but especially the very young and the elderly. Worryingly, norovirus appears to be spreading as the rate of positive tests spike. But what causes this distressing virus, and how can it be treated?
Click through for a detailed prognosis.