Over 1.2m of us puking poms have spent a day or two on our knees in front of the bog over the past few months, and most caught a strain of the vomiting bug called Sydney 2012.

This has  become the ‘dominant strain’ and may explain the huge rise in the number of cases, reports the Daily Mail.

The number of norovirus cases rose as much as 63 per cent compared to last year. In October the Health Protection Agency (HPA) performed genetic testing of norovirus strains in England and Wales and found a ‘cocktail of different strains’ circulating.

But according to recent analysis, Sydney 2012 is responsible for the majority of recent cases in England and Wales affecting 150,000 people over Christmas.

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.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.”

Norovirus is highly contagious and can be transmitted through contact with an infected person or contaminated surfaces and objects. It is known to spread rapidly in closed environments such as hospitals, schools and nursing homes.



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