Viral Pox Spreading Among Squirrel Populations Across the U.S.

Squirrels exhibiting symptoms of a contagious poxvirus, characterized by disfiguring sores and tumors, have been reported in various neighborhoods across the United States. Residents in states including Michigan, Ohio, North Carolina, and Florida have shared images and accounts of squirrels with alarming skin lesions, leading some to dub them 'zombie squirrels.'

Wildlife rehabilitation centers have noted an increase in cases. Halfway Home Wildlife Rehab in Michigan reported taking in several infected squirrels in recent weeks. These animals, such as those named Phlox, Bubbles, and Bugsy, have presented with severe lesions covering their bodies. One squirrel, Phlox, arrived in early June with wart-like growths and was released in late June after showing significant improvement. Bugsy, another squirrel under the center's care, is slowly recovering.

This condition, known as squirrel fibromatosis, is caused by a leporipoxvirus. Experts explain that the virus spreads through direct contact between healthy squirrels and the lesions or saliva of infected individuals, a transmission method comparable to how herpes spreads in humans. The growths can be hairless, appear as tumors, or break open, releasing a clear fluid.

While the visual impact of the disease can be alarming, wildlife officials note that squirrel fibromatosis is a common skin disease among gray squirrels in the U.S. and typically runs its course. Many infected squirrels heal without the need for medical intervention, and the virus is not known to transfer to humans or other animals. However, severe cases can impact internal organs and may be fatal.

Sightings often increase during the summer months when squirrels are more active and forage for food. Wildlife experts suggest that bird feeders, commonly used by homeowners, may unintentionally contribute to the virus's spread. Squirrels can leave saliva on uneaten birdseed, which can then be ingested by healthy squirrels, facilitating transmission. Shevenell Webb of the Maine Department of Inland Fisheries and Wildlife advises against attempting to capture or handle infected squirrels, emphasizing that the virus is naturally occurring and will resolve over time. Some affected animals, like Bubbles at the Michigan rehab center, have presented with pox on their eyes and genitals, with one case complicated by a maggot infestation, underscoring the severity of the disease in some instances.