Cow death sparks virus risk probe

The cow tested negative for known diseases

The mystery death of a cow in Cumbria has sparked a government investigation into any virus risk to humans.

State vets are also examining the unexplained deaths of a further 20 animals as "a matter of urgency".

The alert was triggered by the death of a milking heifer at a farm in Cumbria late last year.

The government's deputy chief vet, Frank Landeg, said the Health Protection Agency is looking into whether humans could be at risk.

Mr Landeg said experts had been looking for any possible human link to the polio-like virus since the milking heifer died before Christmas.

The animal's death could not be put down to any known cattle disease and has sparked concerns that an unknown condition could be in circulation.

Tests on the heifer were carried out at the government's veterinary laboratory in Penrith.

Brain disease

It is thought a virus may be responsible for the condition, described as a type of cattle polio.

But, so far, tests for various known bovine diseases have all proved negative.

At present there is no evidence to suggest a risk to humans, but scientists are not ruling it out.

It is thought the brain disease vCJD originally passed to humans from cows infected with the closely related condition BSE.

Analysis of this cow's brain showed that the disease affected the white matter. This led to paralysis for five to six days, followed by death.

Mr Landeg defended not making details of the investigation public earlier.

He said: "It does take time to put together a group to look at this, bearing in mind what we are talking about here is a possible examination of significance to man.

Cattle polio

"There is a great deal of uncertainty about this."

A spokesman from the Department for Environment and Rural Affairs (Defra) said the case was being carefully investigated.

He said: "The Veterinary Laboratories Agency (VLA) have recorded possibly a new condition in cattle in the UK.

"In layman's terms, a type of cattle polio was identified which we haven't seen before."

The animal was tested for a battery of diseases, all of which proved negative.

The spokesman said no meat from the animal had been allowed into the food chain.

Mr Landeg added: "We are in an area of uncertainty.

"The fact is that we do not know whether there is any significance for man because we have not been able to isolate a causal agent."