Put simply, norovirus is a form of gastroenteritis, a virus which is spread through the air as well as via person-to-person contact and in contaminated or unwashed food. It is highly contagious, meaning that in confined spaces such as hospitals, schools and even cruise ships, widespread infection is common.
Most breakouts can be traced back to just one person. It's called the "winter vomiting bug" in the UK because we tend to spend more time indoors, in close proximity to one another, making it easier to spread from person to person.
Norovirus is so notorious because it spreads incredibly effectively, passing via food, hands and even surfaces. While there is no set way to avoid it, you can take precautions:
Normal alcohol hand sanitisers won't be enough to kill the bug, but they can help to reduce the chances of infection if you can't wash your hands. While it is more common in winter, norovirus can be contracted at any time of the year.
Norovirus has a 24-hour incubation period, which means that if you catch it, it will take around 24 hours for the symptoms to set in.
In the meantime an infected person can still pass it on to other people before it has even been detected. The illness itself lasts between 24-48 hours, and once the symptoms have subsided, you may still be contagious for another 72 hours, so it's a good idea to avoid a trip to the doctor as you may risk passing the illness on.
The symptoms of norovirus are very unpleasant. The illness usually starts with a sudden onset of diarrhoea and severe projectile vomiting, which can continue in waves for up to 48 hours - although many cases are over within about 24 hours.
Stomach cramps, fluctuations in temperature and drowsiness are also common symptoms, both as a result of the body attacking the virus and the exertion of forceful vomiting.
There are no long-term effects from norovirus, even in pregnant people, children and the elderly. If you require medical advice, you should telephone your GP's office rather than going in, to avoid spreading the virus further.
Norovirus can't be treated, but there are certain steps you can take to regain control over your condition and make the experience less uncomfortable.
Staying hydrated is very important, and you should sip water even if you're bringing it back up again. As well as providing the body with water, you're also giving your stomach something to process while it is empty.
The body is trying to flush the virus out of your system, so ensuring there is plenty of water in your digestive system makes the process easier, faster, and far less painful that vomiting on an empty stomach.
Otherwise, try to stay rested as much as possible, and if you can manage it try to eat easily-digestible soft foods like bread.
After the illness has passed you stomach should be back to normal, but you will probably feel a little washed out for a few days, so make sure you rest while the infection clears your system.