The SNP claims hospital hygiene is to blame

The number of confirmed cases in the first three months of 2003 has almost equalled the figure for the whole of 2002.

SNP health spokeswoman Shona Robison said the increase is linked to poor hospital hygiene standards.

But the Scottish Centre for Infection and Environmental Health (SCIEH) said the rise was partly due to better diagnosis.

We don't know whether the nature of the virus is changing and becoming more infectious Prof Bill Reilly SCIEH

Ms Robison said 134 cases of the bug - also known as norovirus - were reported in the first quarter of this year, compared with 187 in 2002.

She said: "They (ministers) need to spend less time privatising cleaning services and more time on the core problem of hygiene.

"It may be cheaper to privatise, but the cost to patients is rising year after year."

But Professor Bill Reilly, of the SCIEH, said the increase could be attributed to a number of factors.

Executive response

Prof Reilly said there was "absolutely no evidence" to suggest the rate of spread hinged on hygiene standards.

He said: "We don't yet know enough about the virus to look at the different strains so we don't know whether the nature of the virus is changing and becoming more infectious."

The virus could also spread in the air when sufferers vomited, he added.

An executive spokeswoman said Ms Robison was wrong to link the bug with hospital hygiene.

She said: "It's quality, not cost that matters when it comes to cleaning services.

"Of the 31 trusts in Scotland, the vast majority of cleaning services are provided in-house."

The virus generally lasts for between 24 and 48 hours and there is no treatment beyond ensuring adequate fluid intake.

It results in projectile vomiting and diarrhoea.