Reports of the infected squirrels date back to mid-2023 but sightings have been made in recent months, the outlet said.
Squirrel fibromatosis, a common skin disease among grey squirrels in the US, isn’t usually threatening to a squirrel’s ability to survive unless the sores spread to its internal organs in rare cases, according to 9News Australia.
Despite their grotesque appearance, the infected rodents don’t pose a threat to humans or common pets like cats and dogs, it reported.
Wildlife biologist Shevenell Webb, of Maine’s Department of Inland Fisheries and Wildlife, told the Bangor Daily News there isn’t much “really to worry about”.
A “zombie squirrel” that was rescued by an animal rehabilitation centre in Michigan, US. Photo / Facebook / Halfway Home Wildlife Rehab
Regardless of the lack of risk, Webb did not recommend trying to help infected animals.
“It [the virus] is naturally occurring and will run its course in time.”
Webb told the outlet the diseased squirrels are, for the most part, “just really ugly to look at”.
Earlier this month, wild rabbits with strange horn-like tumours were spotted around the state of Colorado.
The large tumours, which looked like something out of a horror movie, were caused by Cottontail papilloma virus (CRPV).
A rabbit that has been infected with CRPV. Photo / Supplied
Although the tumours are thought to be painless and typically clear up over time, diseased rabbits may starve if the growths are large enough to prevent them from eating.
Colorado Parks and Wildlife told the Associated Press the virus can not spread to humans or other animals.