Mystery of sickness bug.
A sickness and diarrhoea bug is sweeping across South Wales.
Record numbers of people have already fallen victim to the Norwalk virus, although it is not being treated as an epidemic. Doctors baffled as bug sweeps across region: Mystery surrounds the cause of a major increase in a sickness and diarrhoea bug which has been sweeping through South Wales.
The number of victims of the Norwalk virus has already reached record levels in the first six months of the year.
But health experts have been baffled by the increase as no single epidemic has been reported.
So far this year a total of 269 cases have been diagnosed, compared to 221 for whole of 2005.
Doctors believe the e.coli epidemic, which swept through the Valleys last winter with 150 victims, may have raised public awareness of symptoms which can be similar.
The Norwalk virus causes vomiting, gastric flu, sickness, diarrhoea and fever and lasts from 24 to 48 hours.
It is spread by a lack of toilet hygiene, mainly within families, with the bug spread by food handling.
Cardiff GP Dr Trevor Thompson said doctors had seen many cases but most could be managed by simple advice.
'Those experiencing fever, sickness and vomiting should ensure they keep up their fluid intake and not eat for a short period while the symptoms persist,' he said.
'These symptoms should not last for longer than a few days but the effect can be debilitating and may result in patients feeling unwell for up to a week.'
Chris Lines, of the National Public Health Service for Wales, which monitors disease outbreaks, said: 'There is no obvious explanation for this increase in the Norwalk virus as there have been no large outbreaks.
'We are fairly sure the increased numbers are linked to a better awareness among the public who have sought medical advice and these symptoms have then been reported to us by GPs.'