Cutaneous fibromas are frequently occurring neoplasms naturally occurring virus of white-tailed deer (Odocoileus virginianus). Deer fibromas appear on the skin as hard and round tumors that can be as big as 1 cm in diameter. The tumors are blackish or brown and have a rough textured surface. They do not cause the animal harm unless clumps of fibromas interfere with breathing, eating, or walking. "Fibromas have been reported in white-tailed deer (Odocoileus virginianus), mule deer (Odocoileus hemionus), black-tailed deer (Odocoileus hemionus), fallow deer (Cervus dama), red deer (Cervus elaphus), roe deer (Capreolus capreolus), Sika deer (Cervus nippon), moose (Alces alces) and caribou (Rangifer caribou)." Other common names for fibromas are deer warts or Shope’s warts/fibroma. They are found across the entirety of the whitetail's range.
Contents
Clinical signs and symptoms
The only visible sign of cutaneous fibroma in white-tailed deer are fleshy wart-like growths on the skin, which are likely caused by biting insects. These growths can vary from individual growths to clusters of warts. These warts can also vary in size from small to very large. Because these growths are only attached to the skin, not to the underlying muscle and bone, they actually have no physical effects on the deer itself. These tumors or warts may however impair the ability to see, eat, or run if they are large enough to inhibit normal behavior. Deer with these growths can still be in perfect health and will show no symptoms of ill health.
Transmission of cutaneous fibromas
The transmission of cutaneous fibromas is caused by a microscopic parasite that is transmitted to white-tailed deer through a variety of insect bites or by a white-tailed deer coming in contact with any contaminated object that scratches or penetrates the skin of the deer (Mississippi Department of Wildlife, Fisheries, and Parks). This disease is temporary and only lasts about two months, and appears after about 7 weeks after inoculation of the virus. Cutaneous fibromas are not transmittable to other livestock or humans if the deer is consumed.
Frequency of occurrence
Fibromas occur most frequently in animals under two years of age. The tumor has been diagnosed in 2.1% of males and 0.4% of females. More bucks are shot (either by law or hunter preference), which influences the sampling.
Treatment and control
In most deer, the fibromas develop to only a few mm in diameter. They abruptly stop growing, dry up, and disappear. Only in an occasional deer do they develop into conspicuous skin tumors. Results of the New York survey indicate that wild deer are exposed and develop an immunity to the fibroma virus early in life.
Treatment is not a feasible option for most wild populations. The disease has not been a problem in captive herds. The growths could be removed surgically if it became important, but that would rarely be an issue. Because exposure to the virus leads to immunity, it should be possible to develop a vaccine if prevention becomes necessary. To date, this disease has been too rare to justify such actions.
Significance
Fibromatosis is not an important cause of deer mortality. The disease is not known to infect humans. Although they do not harm the meat, fibromas are repulsive to most people and therefore discourage them from consuming the deer.
Some domesticated animals (cattle, dogs, etc.) are subject to "warts" common to their species. There is no reason to believe that fibromatosis of deer is infectious to domestic animals.