Cutaneous fibromas (also known as deer warts) are common

neoplasms A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

occurring in wild and domestic deer of many species and are caused by host-specific viral infections. The fibromas occur most frequently in animals under 2 years of age, with cases in older deer reported occasionally or rarely. Deer fibromas appear on the skin as hard and round tumors that can be up to 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 The white-tailed deer (''Odocoileus virginianus''), also known as the whitetail or Virginia deer, is a medium-sized deer native to North America, Central America, and South America as far south as Peru and Bolivia. It has also been introduced t ...

(''Odocoileus virginianus''),

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whit ...

(''Odocoileus hemionus''),

fallow deer ''Dama'' is a genus of deer in the subfamily Cervinae, commonly referred to as fallow deer. Name The name fallow is derived from the deer's pale brown colour. The Latin word ''dāma'' or ''damma'', used for roe deer, gazelles, and antelopes, ...

(''Cervus dama''),

red deer The red deer (''Cervus elaphus'') is one of the largest deer species. A male red deer is called a stag or hart, and a female is called a hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Iran, and parts of wes ...

(''Cervus elaphus''),

roe deer The roe deer (''Capreolus capreolus''), also known as the roe, western roe deer, or European roe, is a species of deer. The male of the species is sometimes referred to as a roebuck. The roe is a small deer, reddish and grey-brown, and well-adapt ...

(''Capreolus capreolus''),

Sika deer The sika deer (''Cervus nippon''), also known as the Northern spotted deer or the Japanese deer, is a species of deer native to much of East Asia and introduced to other parts of the world. Previously found from northern Vietnam in the south to ...

(''Cervus nippon''),

moose The moose (in North America) or elk (in Eurasia) (''Alces alces'') is a member of the New World deer subfamily and is the only species in the genus ''Alces''. It is the largest and heaviest extant species in the deer family. Most adult mal ...

(''Alces alces''), and

caribou Reindeer (in North American English, known as caribou if wild and ''reindeer'' if domesticated) are deer in the genus ''Rangifer''. For the last few decades, reindeer were assigned to one species, ''Rangifer tarandus'', with about 10 subspe ...

(''Rangifer caribou'')." They occur across the entirety of the white-tail deer's range.

Clinical signs and symptoms

The only visible signs of cutaneous fibroma in white-tailed deer are fleshy wart-like growths on the skin. These growths can vary from single to clusters of warts. These warts can also vary in size from small to very large. They are only attached to the skin, not to the underlying muscle and bone, so their only physical effects on the deer stem from their ability to impair the deer's sight and range of motion if they are large enough to inhibit normal behavior. Deer with these growths can still be in perfect health and usually show no symptoms of ill health.

Transmission

The fibromas are most often caused by host-specific papillomaviruses. They may also be due to host-specific poxviruses. The transmission of cutaneous fibromas in the white-tailed deer is caused by a virus that is thought to be transmitted through a variety of insect bites or by a deer coming in contact with any contaminated object that scratches or penetrates the skin of the deer or contaminates wounded/damaged skin. Deer tend to frequent particular trails during their movements, and may thus potentially become infected by contact with objects on the path previously contaminated by other deer. As fibromas occur more commonly in bucks, the virus is probably often transmitted during sparring. This disease appears temporary, manifesting after about 7 weeks after inoculation and lasting only about two months. Cutaneous fibromas are not transmissible to other livestock or to humans if their meat is consumed.

Occurrence

Fibromas occur most frequently in animals under 2 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

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 they 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.

Prognosis

Large, ulcerated fibromas are infrequent. In most deer, the fibromas develop to only a few millimeters in diameter. Tumors then regress; this has been observed both in naturally occurring and experimentally induced cases. Only in an occasional deer do they develop into conspicuous skin tumors. Results of a New York survey indicated that wild deer are exposed and develop an immunity to the fibroma virus early in life.

Significance

Fibromatosis The term fibromatosis refers to a group of soft tissue tumors which have certain characteristics in common, including absence of cytologic and clinical malignant features, a histology consistent with proliferation of well-differentiated fibroblast ...

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, so they discourage them from consuming the deer. Some domesticated animals (cattle, dogs, etc.) are subject to "warts" common to their species. Fibromatosis of deer is quite unlikely to be infectious to domestic animals.

Clinical signs and symptoms

Transmission

Occurrence

Treatment and control

Prognosis

Significance

See also

References

Further reading