Mutated wildlife spotted throughout the US has sparked fears that a larger outbreak of infectious diseases may soon threaten humans.
On social media, images of rabbits with tentacles on their faces, squirrels with oozing sores, and deer with massive flesh bubbles on their bodies have poured in from Washington to Minnesota to New York.
Now, experts warn that Americans will see even more disfigured animals in the coming years due to one dangerous factor: disease-carrying insects.
‘This is the season where we see many of those mosquitoes and ticks that are active. We’re not just seeing CRPV, but we’re seeing increases in Lyme disease and other mosquito-borne illnesses and tick-borne illnesses as well,’ Dr Omer Awan of the University of Maryland School of Medicine told the Daily Mail.
Dr Awan noted that the type of heat and moist conditions mosquitoes, ticks, and fleas thrive in has been spreading out into parts of the US that have never dealt with those conditions before. And the viruses affecting rabbits, squirrels, and deer are spread by insect bites.
Throughout the northern US and Canada, squirrels have been spreading squirrel fibromatosis, a virus causing wart-like growths that may ooze fluid but usually heal on their own.
In rabbits, cases of cottontail rabbit papilloma virus (CRPV), also known as Shope papilloma virus, have been spreading north throughout the Midwest, moving from Colorado to Minnesota, Nebraska, and South Dakota.
Americans from the Pacific Northwest to the Northeast have spotted cases of deer cutaneous fibroma, better known as deer warts. This condition is the same viral family as the human papillomavirus, causing growths all over a deer’s body.
A Reddit user recently posted images of a rabbit in Shope papilloma virus in Saint Paul, Minnesota in late July
Deer warts are spread by a virus which is transmitted through mosquito and tick bites. This deer, posted on X, was photographed in Ohio
While the sightings are taking Americans by surprise, experts assured that these grotesque conditions are not new diseases, but are centuries-old viruses that only infect the species carrying them.
Dr Awan emphasized that humans cannot contract any of these conditions from wildlife or the insects that bite them. That’s because each virus will not replicate in a tick or mosquito for it to be transmitted to people.
However, as the summer heat bleeds into more months of the year, the doctor warned that these disease-carrying pests are living longer and invading more states.
That puts more Americans at risk for the other diseases they carry, including Lyme, West Nile, Zika, Dengue Fever, and Chikungunya, all of which are potentially fatal conditions in severe cases.
‘The threat will not likely be year-round but certainly will expand by weeks, if not months, in the year. We will start to see these diseases become endemic in areas not thought to harbor these diseases, which is already occurring,’ Dr Awan explained.
‘This is a prime environment and climate for many of these illnesses to soar. I think it’s sort of a perfect storm for many of these diseases to thrive,’ he added.
AccuWeather has forecasted that the fall will be hotter than normal for parts of 25 states, particularly in the eastern and northwestern US.
AccuWeather’s lead long-range expert Paul Pastelok said: ‘There is a clear trend of hot and sticky summer weather sticking around longer into the back-to-school season across much of the East Coast and many other parts of the country.’
The AccuWeather team added it’s not just the fall forecast that’s a problem; warmer temperatures throughout all of 2025 have affected the number of disease-carrying insects people will see the rest of the year.
Disease-carrying mosquitoes cannot transmit deer warts, squirrel fibromatosis, or cottontail rabbit papilloma virus, but they can infect humans with other illnesses
Residents in Canada have also captured images of infected squirrels who were covered in hairless tumors associated with fibromatosis
‘Warmer, humid weather doesn’t just bring outdoor fun – it can bring mosquitoes. These insects thrive in wet, hot climates. The location’s weather patterns over the past several months can determine how many mosquitoes emerge,’ meteorologists explained.
While climate changes in recent years have helped the virus to spread, Dr Awan noted that there’s one other factor contributing to the increase in mutated animal sightings: social media.
‘People are starting to talk about it more, they’re starting to document it more on social media, and hence, there’s been a lot more discussion about this,’ the doctor explained.
‘When you look at a rabbit, you start to see these outgrowths through the head, the face, the neck. It certainly prompts your attention, and people take pictures of it, and they talk about it,’ he added.
In Colorado, there have been multiple sightings of rabbits with CRPV, particularly near the city of Fort Collins, over the last year.
Colorado Parks and Wildlife (CPW) has urged anyone who sees infected rabbits to stay away and not touch them.
Reports of squirrel fibromatosis, or squirrel pox, date back to 2023, when residents in Maine captured images of common gray squirrels covered in tumors while visiting their backyards.
Squirrel fibromatosis is caused by a virus that cannot be transmitted to people or other animals
A Reddit user posted an image in 2024 of a rabbit in Fort Collins, Colorado, exhibiting signs of Shope papilloma virus
In late June, a Reddit users photographed a young deer with its face completely covered in warts in Milwaukee, Wisconsin
While disease-carrying insects can transmit the virus, wildlife experts believe homeowners who put bird feeders in their yards may have also unintentionally caused the virus to spread to more squirrels who gathered there looking for food.
Shevenell Webb from the Maine Department of Inland Fisheries and Wildlife said: ‘It’s like when you get a large concentration of people. If someone is sick and it’s something that spreads easily, others are going to catch it.’
As for deer warts, the condition is part of the same broad family of viruses that can affect humans, known as papillomaviruses, which target the skin and mucous membranes.
In humans, papillomaviruses cause conditions like common warts, plantar warts, and genital warts, and some strains are linked to cancers such as cervical or throat cancer.
Deer warts can be small, like a pea, or grow as big as a football, appearing gray, black, or fleshy and often hairless.
The condition is rarely fatal. The deer’s immune system fights off the virus, and the warts shrink and disappear on their own after a few months.
In rare cases, if the warts grow too large or become infected with bacteria, they can cause problems like blocking a deer’s vision or ability to eat.