Deadly virus confirmed in red squirrel population

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

Red squirrel standing on the branch of a tree in Scottish woodland

A post-mortem examination of a red squirrel found in Clackmannanshire, carried out at the University’s 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.

Fatal virus

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.

Possible spread

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.

The only other positive case of squirrelpox in a red squirrel north of the central belt was confirmed by the same monitoring scheme near Dunfermline 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.

This newly confirmed case in Dollar Glen indicates that squirrelpox has spread further north in Scotland. Images of other red squirrels from this area with similar facial lesions also raises concerns regarding a more widespread outbreak than the single case identified in March 2024, highlighting the need for increased monitoring and intervention. We are urging members of the public to submit any suspected cases for post-mortem confirmation, as this will help strengthen surveillance and support efforts to limit the spread of squirrelpox in Dollar Glen and the surrounding areas.

It is very upsetting to see red squirrels suffering and dying from squirrelpox in this area. We have a significant population of red squirrels in Clackmannanshire, which people are supportive and protective of. The virus has likely come from grey squirrels spreading into the area from the west of Dollar, where they have travelled north from the grey-only areas of the central belt.

We are looking for volunteers who would be happy to host our live traps in their garden, so we can continue monitoring the red and grey squirrel populations here, and removing grey squirrels to reduce the prevalence of squirrelpox.

Those interested in volunteering with survey or grey squirrel control efforts in the area should contact the Eastern Lowlands Red Squirrel Group (elredsquirrelgroup@gmail.com).

Public guidance

People can report sightings of both red and grey squirrels at scottishsquirrels.org.uk, along with emailing photos of sick reds to Scottish Wildlife Trust (squirrels@scottishwildlifetrust.org.uk).

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.

Guidance on how to effectively clean feeders

Guidance on how to submit a red squirrel for post-mortem examination

Related links

Royal (Dick) School of Veterinary Studies

Easter Bush Pathology, Red Squirrel Mortality Monitoring

Image credit: JohnFScott via Getty Images

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