Mysterious Illness Causes Bizarre Oozing Squirrels to Proliferate in U.S. Backyards

Disturbing Squirrel Illness Spreads Across North America, Linked to Common Garden Habit

Updated August 17, 2025 at 10:30 AM EDT

A concerning outbreak of a skin disease affecting squirrels is being reported across the United States and Canada, raising alarm among wildlife officials and animal lovers. The illness, characterized by grotesque tumors and oozing sores, appears to be linked to a surprisingly common backyard feature.

Reports Surge in 2024 and 2025

Reports of afflicted squirrels began surfacing in 2023, with residents in Maine initially documenting the condition. Images shared on social media platforms like X and reddit depict Gray Squirrels covered in disturbing growths affecting their heads, eyes, limbs, and genitals. Recent cases,posted online in the last month,indicate the problem persists and may be expanding geographically.

Initial speculation pointed to Squirrel Pox, a virus typically impacting Red Squirrels. However, experts now believe the majority of cases involve Squirrel Fibromatosis, a common, though unsightly, condition among Gray Squirrels in North America.

What is Squirrel Fibromatosis?

Squirrel Fibromatosis is caused by a leporipoxvirus, transmitted through direct contact – specifically, through the lesions or saliva of infected animals. It manifests as wart-like tumors that can become open sores. While the condition appears alarming, it’s rarely fatal, and frequently enough resolves on its own within a few months.

Condition	Primary Host	Severity	Transmission	Human Risk
Squirrel Fibromatosis	Gray Squirrels	Generally mild	Direct contact (saliva, lesions)	none
Squirrel Pox	Red Squirrels	Potentially severe	Direct contact	None

Did You Know? Squirrel Fibromatosis does not pose a threat to humans, pets, or other animal species. The virus is species-specific.

The Role of Bird Feeders

wildlife experts suggest that bird feeders may be inadvertently contributing to the spread of the virus. Shevenell Webb of the Maine Department of Inland Fisheries and Wildlife explains the dynamic: “It’s like a large concentration of people. If someone is sick and it’s something that spreads easily, others are going to catch it.”

Squirrels congregating around bird feeders have increased opportunities for transmission through shared food sources and close proximity. Saliva left on uneaten seed can infect other squirrels.

Pro Tip: Consider temporarily removing bird feeders, or regularly disinfecting them, to reduce the risk of spreading the virus among squirrel populations.

one Reddit user described discovering an infected squirrel in their yard on July 31st. “At first I thought it was eating something from my front beds, but then I realized it was on its face,” they posted, highlighting the initial confusion and concern.

Understanding Squirrel Health

Squirrels play a vital role in forest ecosystems, contributing to seed dispersal and forest regeneration.Maintaining their health is crucial for overall environmental balance. Squirrel Fibromatosis, while not typically life-threatening, can impact their ability to forage and avoid predators.Other common squirrel health issues include mange, parasites, and injuries from vehicle collisions. The Wildlife Rehabilitation Facts Directory offers resources for those who encounter injured or sick squirrels.

Frequently Asked Questions About Squirrel Fibromatosis

What are your thoughts on this unsettling trend? Have you observed similar conditions in your local squirrel population? Share your experiences in the comments below.

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What specific pathogens have been ruled out in teh investigation of this novel squirrel disease?

What’s Happening to the Squirrels?

Across the United States, homeowners are reporting a disturbing trend: squirrels exhibiting lesions, oozing fluids, and, in certain specific cases, a generally unwell appearance. This isn’t a localized issue; reports are surfacing from states including Florida, Pennsylvania, and increasingly, across the Midwest. The primary symptom causing concern is the presence of open sores, often around the face, paws, and tail, accompanied by a discharge. While initial speculation ranged from mange to injuries, veterinary pathologists are now pointing towards a novel, and currently unidentified, illness.

This emerging squirrel disease is causing important anxiety among wildlife enthusiasts and pet owners alike. The condition is impacting both Eastern Gray Squirrels (Sciurus carolinensis) and Fox Squirrels (Sciurus niger), the most common species in many areas.

Identifying the Symptoms: What to Look For

Early detection is crucial, even though a definitive diagnosis remains elusive. Here’s a breakdown of the key symptoms to watch for in your local squirrel population:

Visible Lesions: Open sores, scabs, or raw patches of skin. These are often the first sign.

Oozing or Discharge: Fluid leaking from the lesions. The discharge can vary in color and consistency.

Swelling: Inflammation around the affected areas.

Neurological Signs: In some cases, squirrels have exhibited unusual behavior, including appearing disoriented or having difficulty moving. (Though this is less common).

Hair Loss: Patches of missing fur around the lesions.

Lethargy: A noticeable decrease in activity levels. Squirrels may appear sluggish or unresponsive.

Its significant to differentiate these symptoms from common squirrel ailments like squirrel mange, which typically presents with intense itching and hair loss, but less prominent open wounds.

The Current Investigation: What Do Experts Say?

Veterinary diagnostic laboratories, including those at universities like Cornell and Pennsylvania State University, are actively investigating the cause. Initial tests have ruled out common pathogens like rabies, distemper, and tularemia.

Here’s what we know so far:

1. Not a Known Virus: Extensive testing hasn’t identified a known viral agent responsible for the illness.
2. Bacterial involvement Possible: Some labs are exploring the possibility of a bacterial infection, potentially secondary to another underlying cause.
3. Possible Environmental factor: Researchers are investigating potential environmental toxins or pollutants that could be contributing to the outbreak.
4. No Evidence of Human Transmission: As of August 17, 2025, there have been no confirmed cases of human infection related to this squirrel illness. Though, experts advise caution and avoiding direct contact with sick animals.

The Pennsylvania Game Commission has urged residents to report sightings of sick or dead squirrels to help track the spread of the disease. Similar initiatives are underway in other affected states.

Is it Contagious? Transmission Concerns

The method of transmission remains unclear. While it’s not definitively known if the illness is directly contagious from squirrel to squirrel, the increasing number of cases suggests some form of spread. Potential transmission routes being investigated include:

Direct Contact: Through skin-to-skin contact with infected squirrels.

Shared Food Sources: Contamination of nuts,seeds,or other food sources.

Vectors: The possibility of ticks, fleas, or other insects acting as carriers.

Environmental contamination: Exposure to contaminated soil or water.

Protecting Your Pets and Family

While the risk to humans is currently considered low, it’s prudent to take precautions:

Avoid Contact: Do not approach, touch, or attempt to handle sick or dead squirrels.

Pet Safety: Keep pets away from sick or deceased squirrels. If your pet comes into contact with a squirrel, monitor them for any signs of illness and consult your veterinarian.

Bird Feeders & Squirrel Feeders: consider temporarily removing bird feeders and squirrel feeders to reduce congregation and potential spread. Clean feeders thoroughly if you continue to use them.

Garden Hygiene: Wear gloves when gardening and wash your hands thoroughly afterward.

Report sightings: Report any sick or dead squirrels to your local wildlife authorities.

Case Studies & Regional Outbreaks (as of August 2025)

Florida: Initial reports in early 2025 focused on the southeastern portion of the state, with a high concentration of cases reported in Palm Beach County.

Pennsylvania: The Pennsylvania Game Commission has received hundreds of reports of sick squirrels, especially in the eastern and central parts of the state.

Ohio: Increasing reports in the last month suggest the illness is spreading westward.

* Illinois: Isolated cases have been confirmed, prompting increased monitoring by the Illinois Department of Natural resources.

these regional outbreaks highlight the need for a