A VACCINE to protect red squirrels against a deadly disease threatening to wipe them out in the UK is being developed in Scotland.  Scottish scientists say the inoculation could protect Scotland's native species from pox carried by their grey cousins.

The disease leaves the larger greys unharmed but the reds die within weeks of infection. A culling programme is already taking place in Scotland to try to kill the invading greys, which are originally from America.

However, if this does not work, a vaccine could provide a last hope for the native species.

Bob Wilkin, chairman of the Wildlife Ark Trust, the charity funding the research, said: "You just need one grey squirrel with the pox to get into a wood that holds red squirrels and it will wipe them out. At least if you can develop a vaccine then the reds will only be competing for food with the greys."

The vaccine would probably be administered to the squirrels in food, such as peanuts, which would be scattered around woods and forests.

The research is based at the Moredun Research Institute in Penicuik. It will be about two more years before the vaccine is developed, and three years of trials after that before it can be used in the wild.

But Dr Andy Peters, former director of research into vaccines for Pfizer Animal Health, said:

"It could be terrifically beneficial but we cannot predict yet whether it is going to work or not. Hopefully it is going to be successful."

Scotland is home to about 75 per cent of the remaining red squirrels in the UK. Grey squirrels were brought to the UK in the late 19th century. They grow to up to twice the size of the reds, and out-compete them for food and habitat.

However, the most significant factor in declining red squirrel numbers is the greys' deadly pox. Reds develop painful lesions which spread to their eyes and nose. Unable to see, they cannot feed and so starve to death.

Jerry Moss, a red squirrel ranger, said: "I've seen at first hand the awful pain red squirrels suffer when they get squirrel pox. No animal should have to endure that agony. It's vital that we develop a squirrel pox vaccine for the reds."

The Moredun Research Institute is a world leader in livestock vaccine development, as well as being a centre of expertise on squirrel pox.

The research work has attracted widespread support. Wildlife Ark Trust has already raised £320,000 for the research but needs another £88,000.

A European Squirrel Initiative spokesman said: "Preventing the spread of this disease will slow down the demise of the red squirrel and we endorse the Wildlife Ark Trust's efforts."

Dr Peter Lurz of Newcastle University, an expert on red squirrels, said: "Squirrel pox virus is one of the biggest threats to the survival of the red squirrel and a vaccine is a crucial step in trying to safeguard populations in Scotland."

And Advocates for Animals, which opposes the culling of grey squirrels, has called for a squirrel pox vaccine.

To donate visit www.wildlifearktrust.org

Response (Angus)
Conservationists tell us that grey squirrels are the "cause" of the red squirrel decline through the transmission of squirrel-pox virus (SQPV) but there is no evidence to support this. It is merely speculation presented as fact. There are a number of ongoing grant funded studies to try to determine the route of infection but would this expensive research be required if the route was already known?

It is known that the disease characteristics are similar to other poxvirus infections and that most are resistant to drying. This can allow infected lesions or crusts to remain infected for a long time thus allowing the spread of the disease throughout the forest environment by almost any creature that comes into contact with it. Indeed, Scottish Natural Heritage admit they do not know the route of transmission and that "possibilities include being passed by ectoparasites, fleas, lice, ticks and mites which may transfer from animal to animal in the dreys". They also acknowledge the virus may be airborne spread. Research by McInnes et al in 2006 acknowledges "the possibility that the virus is endemic to the UK and that other rodent species inhabiting the same woodland environment could be harbouring the virus.

Under a Freedom of Information request “The Forestry Commission have admitted that no routine testing of live red squirrels is undertaken” and they “are not aware of any scientific evidence one way or another as to whether or not there is a resistant population of reds out there”. So it is quite wrong to claim red squirrels have no immunity to the disease. Indeed, recent research by London zoologists has established that red squirrels are beginning to show signs of natural immunity.

Early in the last century, out of forty-four districts in England where red squirrels had the disease only four districts had grey squirrels present. This suggests that SQPV has been within the red squirrel population for around a century at least.

It is well known that the grey squirrel was brought from America to England in the late 19th Century but less known that ancestors of the current population of red squirrels in the UK have been largely introduced from various parts of Europe. These animals evolved within a wide range of climatic and environmental conditions and associated with different flora and fauna encountered across the part of the range they inhabited, so for conservationists to argue that these influences are not important is to argue against their own concept of “native species”.

Both current populations of squirrels, red and grey, have been introduced to this country and there is no evidence that even the earlier red squirrels evolved here continuously from the time of the land bridge to Europe around 10,000 years ago. Scant archaeological snapshots give no indication of a continued presence. Indeed, prior to the 15th century there seems to be no record of the continuous existence of red squirrel populations living in Britain.

“There is no longer a ‘native’ red squirrel due to the frequent introductions from Europe and habitat defragmentation which has allowed gene flow between previously sub-divided populations.” (Harris et al, 2007)