Scientists are stepping up tests to establish whether a form of rabies found in bats has become endemic in Britain and poses a risk to human health.
A programme to check live bats in Scotland, which began last month, is to be launched in England after vets suggested that existing surveillance was not sufficient.
In addition, research into whether foxes can catch the bat disease lyssavirus has assumed far greater significance because of concern over whether it can transfer to domestic pets and pose a bigger threat to humans.
The increased scientific activity follows the death last year of a Scottish bat enthusiast, David McRae, after he was said to have been bitten by a bat on Tayside. Mr McRae, who was 56, was the fourth person in Europe to die from the bat rabies since 1977 and the first to die from any form of the disease acquired in Britain for a century.
A young bat caught by a cat near a house on the Lancaster canal last summer was found to have lyssavirus - only the second time the strain has been identified in a bat in Britain.
Tony Stevens, a spokesman for the British Veterinary Association and a former head of the government's veterinary laboratory agency, said it was important to discover whether the bat rabies could spread to cats or dogs.
Plans for a pilot bat study in Lancashire, which could be extended to other areas, were announced by the Department of the Environment yesterday.
A veterinary laboratory agency team that investigated Mr McRae's death suggested this week that surveillance was inadequate. "The fact that only two infected bats have been discovered in the UK make it impossible to assess the risk to public health, although it is considered to be low," it said in the Veterinary Record journal.
Britain is officially rabies-free, as judged by the absence of the more common form found in foxes, cats and dogs.
Rabies is nearly always fatal in humans once symptoms linked to the central nervous system occur. Incubation lasts from two weeks to several months and quick vaccination after a bite can save lives. There is mounting evidence that bats can carry the virus without being killed by it.
A dead bat - later identified as having the virus - found in East Sussex in 1996 was assumed to have come from continental Europe. But the Lancashire case was found 230 miles from the continent, making the assumption that bats in Britain are free from the virus more doubtful.
