Diseases and causes of mortality in red squirrels

Squirrelpox

Grey squirrels carry a deadly virus to which they appear immune. When the Squirrelpox virus infects native red squirrels it causes very severe symptoms and ultimately death. The disease is characterised by skin lesions on the face, mouth, feet and anus; these open sores become infected by bacteria and the condition typically leads to death in 2-3 weeks after first infection.

Large proportions of grey squirrels carry the virus and it is not uncommon to find 60-70% of greys have been infected. The presence of this virus is a major reason why grey squirrels should not be allowed to live in areas with red squirrels.

Adenovirus

Adenovirus has been found in both grey and red squirrels on Anglesey. It is unclear if it causes pathological infection in grey squirrels or whether it is passed from one squirrel species to another. What is clear though, is that dead red squirrels are frequently found to have the virus present, and in many cases they show signs of illness associated with the infection.

In 2005, adenovirus was associated with significant numbers of deaths in a red squirrel reintroduction being carries out in Newborough forest. It was subsequently found to be present in 2007 and screening detected infections in animals living elsewhere on the island.

The disease causes lesions in the intestines and severe diarrhea.

Other causes of death

1. Road Traffic

Every year we find between 10 and 15 red squirrels that have been killed on the road. The bodies are collected and sent for Post Mortem and viral screening. These protocols have revealed several cases of animals carrying disease as a subclinical infection; in other words they showed no symptoms but were infected.

2. Domestic Cats

Domestic cats very occasionally catch and kill red squirrels. We have had records of predation of red squirrels from Wern y Wylan and gardens in Menai Bridge. Once again we have sent the bodies away for analysis and they have provided material for genetic research.

Publications

There are many publications relating to disease in red squirrels and we will provide those most relevant to North Wales below:

Adenovirus in Anglesey grey squirrels - Download PDF

Adenovirus infection of red squirrels (UK) - Download PDF

Adenovirus in Angelesy red squirrels - Download PDF

Mortality in red squirrels (UK) - Download PDF

Newborough forest red squirrel reintroduction report - Download PDF

Report dead or sick squirrels

Email: Craig@redsquirrels.info

Telephone 07966150847

In the event that a sick or dead red squirrel is found on Anglesey or in Gwynedd please contact us immediatly.

If the body can be collected, please use gloves and place the remains in a plastic bag. We will then collect from you and pass to our veterinary pathologists for post mortem examinations and viral screening.