Two red squirrels have been fatally infected with squirrel pox virus (SQPV) in Wicklow County, Ireland. The second case was confirmed by the National Parks and Wildlife Services on Friday, Jan. 13. This is the first time that squirrel pox disease has been seen in Ireland.
The story of SQPV underscores the danger of invasive species. The virus arrived in Ireland via the North American grey squirrel, which had been introduced to Britain in the nineteenth century. The grey squirrel has since displaced local British red squirrel populations. Grey squirrels are asymptomatic carriers of SQPV: unlike red squirrels, they are unaffected by the virus. The grey squirrel's resistance to the disease it has introduced into the red squirrel population is seen as a major contributor to decreasing red squirrel populations.
The discovery of the SQPV in Irish red squirrels is quite worrisome. Even before this news, Ireland had seen a 30 percent reduction in red squirrel range by 2009 suspected to be due to the introduction of the grey squirrel. To improve the red squirrel's survival, conservationists have attempted to introduce it into parts of Ireland where neither the red nor grey squirrel currently live.
SQPV was detected in Scotland in 2009. Efforts there are being made to control the grey squirrel population. The Scottish publication The Southern Reporter indicates that grey squirrel populations are moving both southward and westward, potentially endangering other red squirrel populations. There is some controversy regarding the population control, however. Some volunteers are not participating in humane culling of the infected grey squirrels. For this reason, representatives from the Scottish Society for the Prevention of Cruelty of Animals ask residents not to get involved with trapping the grey squirrels.
Symptoms of SQPV in squirrels are similar to symptoms of myxomatosis, a disease that normally occurs in rabbits. They include: skin tumors, runny or swollen eyes, loss of appetite and fever. SQPV can kill red squirrels in a number of days. There are no recorded incidents of SQPV in humans, but people are advised by the National Parks and Wildlife Services to avoid handling sick or dead squirrels.