Causative Agent
  • Lumps, known as papillomas or warts, present on the skin and mucous membranes are benign (non-cancerous) tumors most often caused by the papillomavirus group of viruses.
Click on image to enlarge.
Large, wart-like lesions are fairly common on deer and moose.
  • Worldwide.
  • Throughout the year.
Hosts, Transmission and Life Cycle
  • Papillomas have been described in at least 50 mammalian species.
  • Most commonly observed in moose (Alces alces) in BC, although white-tailed (Odocoileus virginianus), black-tailed and mule deer (O. hemionus) are also reported to be affected occasionally.
  • Occurs through direct contact with warts or lesions of an infected animal that contain virus particles.
  • Transmission may also result when infective lesions are abraded by vegetation that is subsequently in contact with uninfected hosts.
  • Bites of blood-feeding invertebrates (ticks, mites, mosquitoes, etc.) may also transfer the virus.
  • Transmission usually occurs among members of the same species or closely related species. Reports have described areas where several animals are affected over successive years.
Life Cycle:
  • Once infected, lesions may persist for weeks to months.
  • 75-80% of lesions eventually regress, leaving the host immune to future infections.
  • The disease is often self-limiting and lumps usually will disappear; therefore, treatment and control in wild populations is not necessary.
Signs and Symptoms
  • Lesions on the skin and mucous membranes.
  • Lesions can be quite variable in number (few to numerous), size (very small [1-2 mm] to huge [8-10 cm]), coloration (light to dark) and texture (smooth to cauliflower-like in appearance).
  • Animals are generally in good body condition but may become weak and debilitated if the number and size of tumors becomes unusually large or when tumors compromise vision or the ability to eat.
  • Lesions may resemble those of poxvirus infection in birds.
Meat Edible?
  • Meat from infected animals is suitable for human consumption since warts do not affect the quality of the meat.
  • Trim off tissues containing warts prior to consumption for both humans and domestic pets.
Human Health Concerns and Risk Reduction
  • Although unsightly, papillomas are of no consequence to human health, as humans cannot acquire warts from non-primate wild mammals.
Samples for Diagnosis
  • Gross and/or microscopic diagnosis is relatively straightforward.
  • After trimming excess tissue from wart, samples can be placed in a household freezer (-20º C) prior to submission to a suitable laboratory.
Further Reading
  • Alaska Department of Fish and Game – Papilloma
  • Alberta Environment and Sustainable Resource Development – Papilloma (PDF file)
  • Elkin B., Zamke R.L. 2001. Common Wildlife Diseases and Parasites in Alaska. Alaska Department of Fish and Game. Anchorage, AK.
  • Sundberg J.P., Van Ranst M., Jenson A.B. 2001. Papillomavirus infections. Pp. 223-231 in E.S. Williams, I.K. Barker (eds.), Infectious Diseases of Wild Mammals. 3rd Ed. Iowa State University Press. Ames, IA.
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