Tuesday August 1 12:05 PM ET
Scientists Warn of Mad Cow Risk in Dental Surgery

By Kate Kelland

LONDON (Reuters) - British government scientists said on Tuesday there was a theoretical risk that variant Creutzfeldt -Jakob Disease (vCJD), the human form of mad cow disease, could be transmitted from person to person via dental instruments.

The Spongiform Encephalopathy Advisory Committee (SEAC), set up by the government to monitor the brain-wasting disease, told a news conference it had asked the Department of Health to urge dentists to be vigilant in their sterilization practices.

``There is a theoretical risk of person to person transmission of the disease (from dentistry),'' said Peter Smith, acting chairman of SEAC.

He stressed ``the need for thorough cleaning and sterilization practices be observed'' and did not think there was any reason at the moment to recommend changes in dental procedures.

But he also warned: ``Sterilization does not completely inactivate the agent that causes the disease'', and called for a full theoretical risk assessment and further analysis of oral tissue from vCJD patients to improve knowledge of the risk.

SEAC said last month that incidence of the deadly human form of BSE in Britain was increasing by a ``statistically significant'' 20 to 30 percent a year.

Smith said on Tuesday that latest figures show a total of 77 ``definite'' and ``probable'' cases of the disease had been identified in Britain. Eight of those patients are still alive.

Last month the government launched an urgent inquiry into a cluster of CJD deaths around the small village of Queniborough in Leicestershire.

Three of the four victims died within weeks of each other and all lived within a close radius.

Dr Robert Will, head of the government's CJD surveillance unit, said at the time that baby food and school meals may have been a major source for the Queniborough outbreak.

The Health Department has ordered tests of more than 10,000 tonsils and appendices removed since 1985 to find out how many people in Leicestershire have contracted the disease.

Smith said the investigation, which is unlikely to report its findings until the end of the year, might give scientists more clues about the disease.

But he warned that investigations into cluster groups of other diseases did not always prove that useful.

``But that is not to prejudge what is going to happen with the Leicestershire cluster. The hope is of course that this will tell us something.''

Many scientists believe humans contract the disease by eating meat from cattle infected with bovine spongiform encephalopathy (BSE), or mad cow disease.

Outbreaks of BSE all but crippled Britain's beef industry in the late 1990s and provoked a bitter political row within Europe over whose beef was safe to eat.

European Union scientists said on Tuesday that mad cow disease is probably present in cattle in Germany, Spain and Italy even though these countries say they are free of it.

The EU executive said scientists believed that in these states the risk of mad cow infection in cattle was ``likely to be present at levels below the detection limits of their surveillance systems.''