A Wolf’s Tale
Photo courtesy of Hamilton Greenwood
It isn’t every day that a wildlife submission comes to the CWHC with the lesions already discovered. But this was exactly what happened the summer of 2013 when I was working for the CWHC as a veterinary pathologist. My typical cases included autopsies of all sorts of birds, a variety of mammals and even a couple of snakes for good measure. By careful dissection during the autopsy examination and later, by looking at small pieces of tissue under the microscope, I was searching for reasons why these wild animals were sick or died. So when Marnie Zimmer, a wildlife biologist with the CWHC Western/Northern Region, informed me that I had a wolf to look at, I assumed it would be the usual routine. Instead, it started me on a collaborative quest of discovery.
It all started with Don Sussums from Choiceland, Saskatchewan. With over 60 years of experience with wild animals, Don was confident there was something wrong with the skin of this wolf. He decided to submit the wolf to the local Saskatchewan Environment office who then sent it to the CWHC Western/Northern diagnostic laboratory at the University of Saskatchewan for an autopsy and diagnosis. This is where I came in. The skin on the inner thighs had small, white to tan dots. Initially, I was skeptical that these little spots would amount to much but I diligently photographed them and collected samples for further testing.
Thickened areas of epidermis (blue arrow) vs. normal epidermis (red arrow)
Several days later, I received the microscope slides and began examining the magnified pieces of skin. There was skin from normal areas as well as the spots. Under the microscope, the nature of the spots became clear. I was delighted to see these were places where the outer skin layer, called the epidermis, was greatly thickened (Figure 1). I consulted with veterinary pathologist, Dr. Sherry Myers at Prairie Diagnostic Services (PDS). She remarked that these spots were similar to plaques in dogs. Since the plaques in dogs are associated with a papillomavirus, she suggested I test the wolf.
To do this, technicians in the PDS laboratory expose microscope slides to antibodies against the virus. When the virus is present, it stains toffee brown. A quick look under the microscope gave us the answer: there was indeed virus within the spots! (Figure 2). But since we had used antibodies for the dog virus, it wasn’t clear if this wolf happened to pick up the dog virus or if it might be something entirely new.
Brown-staining areas show the presence of virus
To answer this question, I sought the help of Dr. Bruce Wobeser and research technician Betty Lockerbie with the Department of Veterinary Pathology. Using a small piece of the skin with spots, they were able to isolate the DNA and decipher its genetic code. Then, using a computer database called GenBank, they compared our wolf virus to all other known viruses. It turned out to be a distant cousin to a dog papillomavirus. This was the first description of a papillomavirus causing skin lesions in a wolf. It is also the first time DNA from a wolf papillomavirus had its genetic code deciphered.
When I looked through the scientific literature, I found a report of wart-like growths in the mouths and lips of wolves from Alberta. These were likely caused by a papillomavirus too but viral DNA was not examined. This family of viruses causes skin growths in a wide variety of animals including mammals, birds and reptiles. In domestic dogs, which are descendants of wolves, papillomaviruses cause warts on the lips, mouth and skin as well as plaques.
The success of this investigation lies with Don Sussums, the person who submitted the wolf. It was his experience that allowed him to notice the skin problem and his inquisitive nature that drove him to pursue an answer. Citizen scientists like Don have an important role to play in wildlife disease monitoring and I’m thankful to have had the opportunity to pursue this mystery.
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By Dr. Jamie Rothenburger – PhD student, CWHC Ontario/Nunavut
I found the article interesting. I grew up in N.Alberta, farm, and intended to become a Vet. Father said, no money, sorry. So, I became a Biology teacher. I have had dogs as pets. Skin lesions, none I would label as such. But, lumps on a KB Terrier! Seemed to be cysts of a lipid nature.