Squirrelpox virus (SQPV) is a virus that causes the fatal disease squirrelpox in United Kingdom and Republic of Ireland red squirrels. The virus is often carried by grey squirrels from North America, which rarely die from the disease. Elsewhere in the Red Squirrel's European range, either the grey squirrel does not occur or it lacks the poxvirus.
Overview
Grey squirrels very rarely die from this disease as their population has developed immunity having been exposed to the virus for many years; however, they are still carriers of the infection and can spread the disease to red squirrels. In sharp contrast, there are no known red squirrels that have developed immunity to the disease, and the mortality rate for untreated infected squirrels in the wild appears to be 100%, most dying within 4–5 days of being infected.
There has been some more recent anecdotal evidence on resistance to squirrel pox in the red population including the finding of a healthy red squirrel with antibodies to the virus in Cumbria. However the mortality rate is still considered severe, and certainly capable of local extinction of red squirrels in areas that succumb to the disease.
Taxonomy
The ICTV abbreviation for Squirrelpox virus is SQPV.
Transmission
The virus can spread through contact with the infected lesions or contaminated crusts, and can also be carried by mosquitoes. Fleas are another vector for the disease. Most poxviruses are highly resistant to drying, which allows crusts to remain infectious for long periods of time. It is believed that the virus can be transferred by contaminated feeders, which is why red squirrel preservation organizations often recommend that feeders are disinfected daily. Many poxviruses are potentially zoonotic, and other poxviral infections have been reported in man. However, no cases of transmission to humans are known. Most of these are in Scotland. The decline of red squirrels is blamed mostly on disease, the loss of woodlands, and competition by grey squirrels. There are over 2.5 million grey squirrels in the British Isles. Red squirrels' survival chances in conifer woods are much higher than in deciduous woods.
<!-- Image with unknown copyright status removed: thumb|right| -->== Vaccine Development ==
In early 2023, over 11,000 people signed a petition to the Welsh Senedd calling for research into a vaccine to be restarted. Promising virus attenuation studies had ended a decade earlier in 2013 after funding ran out.