Warning on rise in norovirus cases
Writing in the journal Eurosurveillance, they said it may be a severe norovirus season ahead.
Several countries, including Australia, New Zealand, Japan and France, reported increased levels of norovirus in late 2012.
In England there has been a dramatic rise in hospital outbreaks, a 64% increase in the number of laboratory confirmed cases in England and Wales, as well as reports from Japan of deaths among the elderly.
International surveillance data suggests increases in Australia, New Zealand, Japan and France appear to be associated with the emergence of a new variant of genotype II.4, dubbed