Deadly virus confirmed in red squirrel population

Experts have confirmed squirrelpox virus in red squirrels north of Scotland’s central belt for the second time in two years.

A post-mortem examination of a red squirrel found in Clackmannanshire, Scotland, carried out at the Royal (Dick) School of Veterinary Studies, confirmed that the virus is present in the population.

Video recordings of red squirrels in the area suggest further spread of the virus. The findings pose a major threat to Scotland’s more northerly red squirrels, experts say.

People living in the region are urged to remain vigilant and take action to help reduce the spread of the disease, by recording sightings of affected squirrels and removing garden feeders, which can enable disease spread.

Squirrelpox is a virus carried by grey squirrels. It does not affect greys, but can be rapidly lethal when passed to red squirrels. 

Symptoms include ulcers, scabs and weeping lesions on the face, particularly around the mouth and eyes, which can prevent reds from eating, drinking or moving. It is usually fatal within two weeks and if left unmanaged, an outbreak can cause local populations to crash.

When squirrel pox is present, greys can replace red populations around 20 times as fast as they can through competition alone, scientists say.

The potential of an outbreak was first alerted to Saving Scotland’s Red Squirrels (SSRS) and the Eastern Lowlands Red Squirrel Group (ELRSG) in June, when a member of the public photographed an unwell red squirrel in Dollar Glen, Scotland.

The only other positive case of squirrelpox in a red squirrel north of Scotland’s central belt was confirmed by this monitoring scheme near Dunfermline, Fife in March 2024 – approximately 15 miles south from the most recent case.

Conservation groups are currently monitoring another red squirrel with possible signs of the virus, seen in nearby Devilla Forest in Fife. 

Squirrelpox can only be fully confirmed in red squirrels following a post-mortem examination, so it can be difficult to get a full understanding of the virus, experts say.

People can report sightings of both red and grey squirrels to the Scottish Squirrels website, and email photos of sick reds to the Scottish Wildlife Trust.

Although squirrelpox is not considered harmful to humans, anyone who sees a sick-looking red squirrel is advised not to approach it, but instead contact Saving Scotland’s Red Squirrels for advice.