Cutaneous fibromas (also known as deer warts [1] ) are common neoplasms occurring in wild and domestic deer of many species and are caused by host-specific viral infections. [2] [3] [4] The fibromas occur most frequently in animals under 2 years of age, with cases in older deer reported occasionally or rarely. [2]
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 (Odocoileus virginianus), mule deer (Odocoileus hemionus), fallow deer (Dama dama), red deer (Cervus elaphus), roe deer (Capreolus capreolus), Sika deer (Cervus nippon), moose (Alces alces), and caribou (Rangifer caribou)." [5] They occur across the entirety of the white-tail deer's range. [1]
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. [6]
The fibromas are most often caused by host-specific papillomaviruses. They may also be due to host-specific poxviruses. [1] [4]
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. [6] [4] 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. [2] As fibromas occur more commonly in bucks, the virus is probably often transmitted during sparring. [4]
This disease appears temporary, manifesting after about 7 weeks after inoculation and lasting only about two months. [6] Cutaneous fibromas are not transmissible to other livestock or to humans if their meat is consumed. [7]
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. [5]
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. [7]
Large, ulcerated fibromas are infrequent. [2] 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. [8] [2]
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, so they discourage them from consuming the deer. [7]
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. [7]
Warts are non-cancerous viral growths usually occurring on the hands and feet but which can also affect other locations, such as the genitals or face. One or many warts may appear. They are distinguished from cancerous tumors as they are caused by a viral infection, such as a human papillomavirus, rather than a cancer growth.
Myxomatosis is a disease caused by Myxoma virus, a poxvirus in the genus Leporipoxvirus. The natural hosts are tapeti in South and Central America, and brush rabbits in North America. The myxoma virus causes only a mild disease in these species, but causes a severe and usually fatal disease in European rabbits, the species of rabbit commonly raised for companionship and as a food source.
Chronic wasting disease (CWD), sometimes called zombie deer disease, is a transmissible spongiform encephalopathy (TSE) affecting deer. TSEs are a family of diseases thought to be caused by misfolded proteins called prions and include similar diseases such as BSE in cattle, Creutzfeldt–Jakob disease (CJD) in humans, and scrapie in sheep. Natural infection causing CWD affects members of the deer family. In the United States, CWD affects mule deer, white-tailed deer, red deer, sika deer, elk, bison, squirrels, antelope, caribou, and moose. The transmission of CWD to other species such as squirrel monkeys and humanized mice has been observed in experimental settings.
A plantar wart is a wart occurring on the bottom of the foot or toes. Its color is typically similar to that of the skin. Small black dots often occur on the surface. One or more may occur in an area. They may result in pain with pressure such that walking is difficult.
Papillomaviridae is a family of non-enveloped DNA viruses whose members are known as papillomaviruses. Several hundred species of papillomaviruses, traditionally referred to as "types", have been identified infecting all carefully inspected mammals, but also other vertebrates such as birds, snakes, turtles and fish. Infection by most papillomavirus types, depending on the type, is either asymptomatic or causes small benign tumors, known as papillomas or warts. Papillomas caused by some types, however, such as human papillomaviruses 16 and 18, carry a risk of becoming cancerous.
The mule deer 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.
Parelaphostrongylus tenuis is a neurotropic nematode parasite common to white-tailed deer, Odocoileus virginianus, which causes damage to the central nervous system. Moose, elk, caribou, mule deer, and others are also susceptible to the parasite, but are aberrant hosts and are infected in neurological instead of meningeal tissue. The frequency of infection in these species increases dramatically when their ranges overlap high densities of white-tailed deer.
Bovine papillomaviruses (BPV) are a paraphyletic group of DNA viruses of the subfamily Firstpapillomavirinae of Papillomaviridae that are common in cattle. All BPVs have a circular double-stranded DNA genome. Infection causes warts of the skin and alimentary tract, and more rarely cancers of the alimentary tract and urinary bladder. They are also thought to cause the skin tumour equine sarcoid in horses and donkeys.
Elaeophora schneideri is a nematode which infests several mammalian hosts in North America. It is transmitted by horse-flies. Infection in the normal definitive hosts, mule deer or black-tailed deer, seldom produces clinical symptoms. In other hosts, such as sheep, elk, moose, and goats, infection with E. schneideri leads to elaeophorosis. Symptoms of elaeophorosis include necrosis of the muzzle, ears, and optic nerves; lack of coordination (ataxia); facial or lower limb dermatitis; horn deformities; blindness; and death.
Epizootic hemorrhagic disease (EHD) is a hemorrhagic disease of white-tailed deer caused by an infection of a virus from the genus Orbivirus subsequently called Epizootic hemorrhagic disease virus (EHDV). It is an infectious, and sometimes fatal, virus that is characterized by extensive hemorrhages, and is found throughout the United States. Large-scale outbreaks in wild ruminants affect livestock and the production industry. EHD has been found in some domestic ruminants and many species of deer including white-tailed deer, mule deer, elk, and pronghorn antelope. Seropositive black-tailed deer, fallow deer, red deer, wapiti, and roe deer have also been found, which essentially means that they were exposed to the disease at some time in the past but may not be involved in transmission. Outbreaks of EHD have been reported in cattle, although they rarely develop disease or die. Sheep may develop clinical signs, but this is also rare. EHD is often called bluetongue, but this is incorrect. Bluetongue virus is closely related to EHDV, and has similar clinical signs, but it is a different disease. Bluetongue is a serious disease in cattle, as well as other ruminants, and can have a significant effect on international trade. Testing at animal health laboratories is necessary to distinguish between the viruses that cause bluetongue and EHD.
The Shope papilloma virus (SPV), also known as cottontail rabbit papilloma virus (CRPV) or Kappapapillomavirus 2, is a papillomavirus which infects certain leporids, causing keratinous carcinomas resembling horns, typically on or near the animal's head. The carcinomas can metastasize or become large enough to interfere with the host's ability to eat, causing starvation. Richard E. Shope investigated the horns and discovered the virus in 1933, an important breakthrough in the study of oncoviruses. The virus was originally discovered in cottontail rabbits in the Midwestern U.S. but can also infect brush rabbits, black-tailed jackrabbits, snowshoe hares, European rabbits, and domestic rabbits.
The Capreolinae, Odocoileinae, or the New World deer are a subfamily of deer. Alternatively, they are known as the telemetacarpal deer, due to their bone structure being different from the plesiometacarpal deer subfamily Cervinae. The telemetacarpal deer maintain their distal lateral metacarpals, while the plesiometacarpal deer maintain only their proximal lateral metacarpals. The Capreolinae are believed to have originated in the Middle Miocene, between 7.7 and 11.5 million years ago, in Central Asia.
Cutaneous horns, also known by the Latin name cornu cutaneum, are unusual keratinous skin tumors with the appearance of horns, or sometimes of wood or coral. Formally, this is a clinical diagnosis for a "conical projection above the surface of the skin." They are usually small and localized but can, in very rare cases, be much larger. Although often benign, they can also be malignant or premalignant.
Angiofibroma (AGF) is a descriptive term for a wide range of benign skin or mucous membrane lesions in which individuals have:
Infantile digital fibromatosis (IDF), also termed inclusion body fibromatosis or Reye's tumor, usually occurs as a single, small, asymptomatic, nodule in the dermis on a finger or toe of infants and young children. IMF is a rare disorder with approximately 200 cases reported in the medical literature as of 2021. The World Health Organization in 2020 classified these nodules as a specific benign tumor type in the category of fibroblastic and myofibroblastic tumors. IDF was first described by the Australian pathologist Douglas Reye in 1965.
Gérard Orth was a French virologist, emeritus research director at the CNRS, honorary professor at the Pasteur Institute.
Fibroblastic and myofibroblastic tumors (FMTs) are tumors which develop from the mesenchymal stem cells which differentiate into fibroblasts and/or the myocytes/myoblasts that differentiate into muscle cells. FMTs are a heterogeneous group of soft tissue neoplasms. The World Health Organization (2020) defined tumors as being FMTs based on their morphology and, more importantly, newly discovered abnormalities in the expression levels of key gene products made by these tumors' neoplastic cells. Histopathologically, FMTs consist of neoplastic connective tissue cells which have differented into cells that have microscopic appearances resembling fibroblasts and/or myofibroblasts. The fibroblastic cells are characterized as spindle-shaped cells with inconspicuous nucleoli that express vimentin, an intracellular protein typically found in mesenchymal cells, and CD34, a cell surface membrane glycoprotein. Myofibroblastic cells are plumper with more abundant cytoplasm and more prominent nucleoli; they express smooth muscle marker proteins such as smooth muscle actins, desmin, and caldesmon. The World Health Organization further classified FMTs into four tumor forms based on their varying levels of aggressiveness: benign, intermediate, intermediate, and malignant.
Gardner fibroma (GF) is a benign fibroblastic tumor. GF tumors typically develop in the dermis and adjacent subcutaneous tissue lying just below the dermis. These tumors typically occur on the back, abdomen, and other superficial sites but in rare cases have been diagnoses in internal sites such as the retroperitoneum and around the large blood vessels in the upper thoracic cavity. The World Health Organization, 2020, classified Gardner fibroma as a benign tumor in the category of fibroblastic and myofibroblastic tumors.