It’s shut down schools, closed oil rigs and forced cruise ships back to dock early, but what exactly is the norovirus?
The number of Brits suffering from norovirus is at its highest since 2011.
Data from Public Health England shows reports of the vomiting bug are at 2,435 so far this winter – 12% above the average for the same period over the last five years.
The figure is 71% higher than the same period last year, though last winter saw unusually low levels.
In the week up to Christmas Day, vomiting and diarrhoea outbreaks resulted in an average of 699 bed closures a day, up from 559 in the same period last year.
Hospitals reported 20 norovirus outbreaks in the first two weeks of December – 17 of which led to bay or ward closures and 13 of which were confirmed as the bug.
Some scientists attribute the winter upsurge to cold weather snaps – such as the one we had mid-December, driving everyone indoors, where germs spread easier.
But it is also thought that a new strain called Sydney 2012, to which few are resistant, could be the reason for the sharp rise in cases this winter.
So what is norovirus?
The winter norovirus is a particularly contagious bug that affects nearly one million Brits each year, and causes up to two days of diarrhoea and projectile vomiting as well as fluey symptoms.
This particular strain of stomach bug – or gastroenteritis – can be caught at any time of year but it often flares up in the winter, as cold weather forces us indoors, creating damp conditions that are ideal for helping it to spread easily.
“Norovirus is known as the winter vomiting bug because the virus causes increased cases during the winter period,” says David Lawrence of the Health Protection Agency.
“In fact, it has been estimated that it accounts for around 90% of non-bacterial gut infections worldwide. The distinctive symptom of norovirus is a sudden onset of nausea.”
What causes it?
The virus can be transmitted by contact with contaminated surfaces or objects, contact with an infected person, or by the consumption of contaminated food or water.
The bacteria can live on surfaces for up to five days and is impossible to spot. Places such as train carriages, buses or offices are hotbeds for them – so much so, that experts encourage anyone who thinks they might be carrying the bug to stay away from built-up areas.
Can it be avoided?
While most of us won’t be able to go into quarantine for the rest of winter, maintaining high standards of hygiene is vital to avoiding the bug.
“Norovirus is very contagious, and anyone who has had it knows it is very unpleasant,” says John Harris.
“If you think you may have the illness then it is important to maintain good hand hygiene to help prevent it spreading.
“We also advise that people stay away from hospitals, schools and care homes as these environments are particularly prone to outbreaks.”
Just a single particle from a cough or sneeze can contain enough bacteria to pass on the virus, but using hand sanitiser wipes or gel will kill the germs before they spread.
Maintaining a strong immune system by getting the recommended daily allowance of five portions of fruit and veg and cutting back on alcohol and cigarettes will also help to stave off infection.
For those affected by the virus, the NHS recommends remaining in quarantine for up to 48 hours after symptoms have passed to prevent further contamination. Disinfect toilets, bathroom surfaces and door handles. And don’t share towels.
Children who have had the bug should avoid communal swimming pools for up to two weeks after any bouts of diarrhoea.
Can it be treated?
“There isn’t any particular treatment for norovirus,” says Paul Zollinger-Read, BUPA’s chief medical officer.
“But if you are infected it’s important to drink lots of fluids to avoid dehydration.
“Stay at home and take paracetamol if you are aching or have a high temperature.
“Wash your hands regularly, too, to prevent it spreading. If you are hungry you should eat food that can easily be digested.
“Immunity to the virus only lasts a short time,” adds Paul.
“Therefore, having had the virus in the past doesn’t mean you won’t get it again and, as it’s a virus, antibiotics will not help.”
Although symptoms can be extreme, the NHS advises there’s no need to contact your doctor unless the illness lasts longer than 48 hours.
Those already suffering other ailments or ones who have more serious health issues should contact their GP, while young children and the elderly should be monitored.
“While generally there are no long-term complications, the illness may take a little longer to clear up in some people,” says David Lawrence.
“If you are still unwell after three or four days, symptoms are particularly severe, or you have blood in your stools it is advisable you call your GP.”
It’s important sufferers increase their water intake to replace fluid lost through vomiting and diarrhoea.
Rehydration sachets, available from most chemists, help rebalance the bodies’ salt and sugar levels.
Will we find a cure?
Scientists have developed a ‘vomiting robot’ to help detect how far microscopic particles of sick can carry the virus.
According to Prof Ian Goodfellow, who has spent 10 years trying to cure norovirus, the speed at which it can spread makes the bug ‘the Ferrari of the virus world’.