Many people laid low by a recent vomiting bug have a new strain of norovirus, according to the Health Protection Agency (HPA).
Sydney 2012, a strain first detected in Australia, has been blamed for a recent outbreak which first emerged in October.
At first the HPA discovered a number of strains when vomiting cases began to increase three months ago, but further testing revealed that Sydney 2012 had become the dominant strain.
Although other strains of norovirus have been detected, the majority of the recent vomiting cases in England and Wales have been caused by Sydney 2012, the HPA has confirmed.
The good news for healthcare professionals charged with treating those with the norovirus is that it is no more harmful than other strains. It has also been identified in France, New Zealand and Japan.
The HPA revealed that 4,140 cases had been reported this season, but also went on to add that some 288 cases are not reported for every case that is. This means that 1.19 million people could have contracted the norovirus this season. This amounts to 63% more cases than during the previous year.
Director of HPA’s virology reference department Dr David Brown 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.
“At the start of the season it is normal for outbreaks to be caused by a range of different strains. However, as the season progresses particular strains are more successful and become dominant. The emergence of a new strain does not mean that it causes more serious illness.
“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.”