UniquePetsWiki is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Read more

Squirrel Pox: A Disease to Be Aware Of

Squirrel pox is a disease caused by poxvirus associated with the introduced American grey squirrel which has been recognized as playing a major role in the reduction of the number of red squirrels because they seldom recover from it. In grey squirrels, the poxvirus is a sub-clinical infection that rarely manifests in disease. 

But, in red squirrels it causes ulceration with crusted lesions and scabs around the eyes, lips, feet and genitalia, and an exudative dermatitis which may be mis-diagnosed due to other similar looking diseases.

Although both squirrel species are susceptible to being infected with the poxvirus, grey squirrels are believed to have strong immunity to the disease. Also, grey squirrels act as direct competitors to red squirrels for habitat and resources and appear to be able to out-compete them.

An animal can contract a disease, and it’s always challenging to suspect any particular illness unless you are familiar with its signs. Do you agree with me? If I tell you that squirrels never fall sick, then this will be a big lie.

Thank you so much for finding time to read my article. We will dig deep into squirrel pox diseases, the transmission, symptoms, treatment, and significance of the disease. Please don’t stop here; let’s dive into the article for more information.

This article has been reviewed by Dr. Linda. Read more about our knowledge control process here.

What is Squirrel Pox?

Squirrel pox is a viral infection that produces swollen lesions on the squirrel’s skin. It affects the nose, eyes, flanks, ears, front jaws, head, and around the mouth. The signs are majorly visible in red squirrels.

Squirrel pox and squirrel fibroma all mean the same thing; people use them interchangeably. The term pox isn’t new to us. It has been around us for a couple of years. A pox is an illness associated with a rash of pimples that may leave pockmarks upon healing.

Pox disease affects many species of animals. For instance, we have rabbit pox, chickenpox, fowl pox, sheep pox, horse pox, cowpox, smallpox, monkeypox, etc. whoops! I forgot to mention squirrel pox, but you know it already.

That’s done; let me stop deviating and explain squirrel pox frankly. So, what is squirrel pox? Squirrel pox is a viral infection that produces swollen lesions on the squirrel’s skin. It affects the nose, eyes, flanks, ears, front jaws, head, and around the mouth. The signs are majorly visible in red squirrels.

squirrel pox is squirrel in nature
Squirrel pox is a disease attributed to squirrels alone. Thus, humans cannot contract it.

Squirrel Pox Origin and Distribution

The outbreak of squirrel pox infection has been happening for over a century now. However, about which country squirrel pox originated from remains unknown to date. Although, the first case of the disease was confirmed in East Anglia in the 1980s.

From East Anglia, squirrel pox was again confirmed in Lancashire in 1995-1996, Cumbria in 1998, Durham and Northumberland in 1999. The disease has also been reported in Scotland, Ontario, and some states in North America.

Grey squirrels are believed to be exposed to squirrel pox for many years; hence, they have strong immunity to the infection. These squirrels’ species are famous carriers of squirrel pox.

Squirrel Pox Aetiology and Transmission

The squirrel pox virus causes squirrel pox. Some studies group the virus in the family poxviridae, although its classification is still under debate.

I mentioned earlier that grey squirrels are primarily immune to squirrel pox infection; they rarely succumb to the disease. The highest rate of transmission occurs from grey squirrels to red squirrels.

The spread of the disease occurs mainly through contact with contaminated objects, infected lesions, and parasites like mosquitoes. Parasites are the significant transmitters of poxvirus from grey to red squirrels. 

Most poxviruses are incredibly resistant to drying, and therefore, the resulting lesions are infectious for quite a long time. An infected squirrel introduces the virus to healthy squirrels when they come in direct contact.

Moreover, the squirrel feeders are the route for the spread of the disease if they are contaminated. It happens mostly among red squirrels when they are feeding together on the same feeder. Red squirrels are also famous for spreading the infection to each other in feces and saliva.

Clinical Signs of Squirrel Pox

It is easy to spot a squirrel suffering from squirrel pox infection as the symptoms are observable. Juvenile squirrels are more vulnerable to the disease compared to adults. An infected animal will show the following signs:

  • Skin lesions, scabs, and ulcers are common in red squirrels.
  • Discharge and swelling on lesions near the mouth, feet, eyes, genitalia, or all over the body. The lesions vary in size and can go up to 25mm in diameter.
  • Lethargy as the disease develops.
  • Shivering
  • Metastasis to the lymph nodes, lungs, kidney, and liver.
  • Mortality is 100% after 15 days without treatment in red squirrels.
  • Anorexia
  • The animal is more approachable and tends to take a lot of water.
  • Swelling.

Infected animals are unable to feed themselves, and therefore, most deaths are because of starvation. Grey squirrels usually don’t show any signs of the disease and can survive with it for a long time.

A squirrel with squirrel pox is likely not to survive it
A squirrel with squirrel pox is likely not to survive it

Control and Treatment

A squirrel diagnosed with squirrel pox and exceeds the incubation period for the disease, which is, two weeks, has no hope for recovery. However, does it mean that there are chances for these cute innocent creatures to heal in the initial stages?

The truth is that squirrel pox has no known treatment. But if the disease isn’t severe, the lesions can regress, and eventually, the animals recover completely. It’s possible to control this disease through an injectable vaccine.

During the outbreak of squirrel pox, it’s advisable not to feed squirrels on the same feeder to avoid contact. Also, if you suspect there is an infected squirrel, make sure to inform the local red squirrel group.

Even after learning that squirrel pox doesn’t affect humans, it’s necessary to wash your hands after touching any sick animal, even squirrels. The squirrel may be a carrier of other pathogens that might be harmful to you.

Do Squirrels Transmit Squirrel Pox to Humans?

Have you heard of any reported cases of squirrels spreading the squirrel pox virus to humans? It’s a common question on the internet. Anyway, it’s essential to know diseases transmissible from animals to humans for our safety.

About squirrel pox, this is a disease of squirrels in nature. Even the laboratory tests confirm that this virus cannot survive in humans. That’s good news, especially to squirrel owners knowing they aren’t at any risk.

Likewise, the carcass from dead infected squirrels doesn’t pose any danger to human beings. It is not something new that some people consume the meat of squirrels that die of this disease.

Although human beings are not infected by squirrel pox, the disease is transmittable to some animals such as rabbits and woodchucks. This has only happened in the lab, never in the wild.

A documentary on squirrel pox [source: Emma Small]

Wrapping Up

Squirrel pox is a squirrel’s disease in nature. It affects several squirrel species, e.g., fox, red, and gray squirrels. But gray squirrels, although they contract the infection, it doesn’t affect them severely. Only a few death cases of squirrel pox are reported in gray squirrels.

But in red squirrels, it’s a very different case. They are adversely affected by the disease and register mortality of almost 100%. One gray squirrel is enough to spread the disease to a population of red squirrels.

Since there is no treatment for squirrel pox, vaccination against the disease is recommended, but this would be difficult to control in wild squirrels.

About UniquePetsWiki

UniquePetsWiki is the preferred educational source on pets favored by experienced herptologists and new owners alike. With hundreds of articles on everything pertaining to pets including reptiles, squirrels, and other pets, our experienced team provides reliable and accurate content you can trust.

From proper husbandry and habitat guidance, to articles on health concerns, diet, and extensive care guides, UniquePetsWiki is here to educate everyone on all pets concerns.


UniquePetsWiki is not a veterinary website, nor should any of the reptile health information on our site replace the advice of a certified veterinary professional. If your pet is experiencing a medical emergency, contact an experienced veterinarian immediately.

UniquePetsWiki is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.