Squirrel Pox

Healthy Baby Squirrel - October 2012

October 4^th is celebrated as the Roman Catholic feast day of Francis of Assisi, patron saint of animals and nature.  So it seems like an appropriate day to write about an animal that has touched my heart this week.

On Thursday I saw a gray squirrel bound across the backyard. He was moving fast but I could tell that something was wrong with his front leg. It was bright red and devoid of fur. By the time I got my binoculars, the squirrel was gone.

The next day he returned, joining the other squirrels in the feeder area directly behind the house. Now I could see that what I had initially thought was an injury was in fact a bad case of Fibromatosis commonly known as squirrel pox.

Michigan is known to have frequent outbreaks of the disease. Affecting young squirrels, it is believed that the virus is transmitted by insect bites.  During my time as a wildlife rehabitator, I never admitted or cared for a squirrel with the disease. However, that the source of the disease came from insects was no surprise as my experience in raising orphan squirrels always began with treating them for fleas and other infestations.

The virus manifests itself through the growth of tumors (pox) that emerge on the skin surface. In extreme cases the pox may metastasize internally but what I have been able to research indicates that the disease doesn’t in itself directly cause death. Death comes from by the squirrel’s inability to maintain a normal life. Should the pox invade the mouth; eating becomes difficult with starvation its natural course. The pox may cover the eyes, or enlarge the paws to the point that escape from predators is impaired. Injuries to the pox themselves can result in an infection that can also kill the squirrel.

I found an article from a rehabilitator that with the application of drying medications to the pox and antibiotics for infections, the squirrel can be successfully treated and released. Because of the abundance of squirrels and the fact that an infected squirrel can still be hunted and consumed without fear of disease transmittal to humans, little effort is made to combat the disease system-wide by wildlife managers.

Despite the numerous poxes on his body, my squirrel is able to run, climb and eat without difficulty. There is always a risk that the pox will compromise his ability to survive but at this point, he is doing fine. I will continue to monitor his health and if given the opportunity, will attempt to live-trap him for treatment. 

I taped his visit yesterday and have linked it below for viewing. For those who are squeamish of growths, please be aware that I tried to capture as many of the pox for my own research purposes. But realize that in spite of the pox, this squirrel is behaving no differently than a healthy one.