Squirrelpox virus (SQPV) causes the fatal disease squirrelpox in red squirrels in the United Kingdom and the Republic of Ireland. The virus is commonly carried by grey squirrels from North America, which rarely die from it but can transmit it to red squirrels. Red squirrels, on the other hand, have not developed immunity, leading to a mortality rate of nearly 100% among untreated infected individuals, with most dying within 4 to 5 days.
The virus spreads through contact with infected lesions, contaminated scabs, and possibly through mosquitoes. It can also be transmitted via contaminated feeders, prompting red squirrel preservation groups to recommend daily disinfection of feeders. Although many poxviruses are zoonotic, no cases of squirrelpox transmission to humans have been reported.
