UK & World News
Norovirus: Vomiting Bug Spread From Australia
A new strain of norovirus, which spread from Australia, is responsible for the majority of recent cases, health experts have said.
The new variant of the bug, called Sydney 2012, has become the "dominant strain", officials said.
In October, when the number of cases started to increase, the Health Protection Agency (HPA) performed genetic testing on norovirus strains in England and Wales.
They found a "cocktail of different strains" that were circulating around the population.
However, recent analysis has shown that Sydney 2012 - first identified in Australia last year - has overtaken all others to become the dominant strain responsible for most of the recent cases in England and Wales.
Health officials said that Sydney 2012 has also been identified by health experts in France, New Zealand and Japan, but does not cause any worse symptoms than other strains.
The HPA said there have been 4,140 laboratory-confirmed cases of norovirus so far this season - but for every reported case, an estimated 288 are not flagged up.
This means as many as 1.19 million people could have contracted the illness this winter - a 63% rise on the previous year.
Dr David Brown, director of Virology Reference Department at the HPA, said: "It is always difficult to predict the norovirus season and this year is no different.
"Noroviruses mutate rapidly and new strains are constantly emerging."
There is no specific treatment for norovirus infection other than to let the illness take its course, with symptoms usually lasting around two days.
"Keeping hydrated is very important and you can take over-the-counter medicines to relieve headaches and aches and pains," added Dr Brown.
Norovirus is highly contagious and can be transmitted through contact with an infected person or contaminated surfaces and objects.
Symptoms include sudden vomiting, diarrhoea, or both, a temperature, headache and stomach cramps.