Papillomas, or warts as they are commonly called, are caused when a papillomavirus infects skin cells. Warts are a type of benign skin tumor and should be differentiated from papillomatosis, which are wartlike lesions that can occur on the surface of the cloaca or along the gastrointestinal tract in psittacine birds. Recent research suggests that papillomatosis is probably caused by a virus.
Several distinct papillomavirus have been documented in companion and aviary birds. It is probable that other variants of this virus will be identified in psittacine birds. These viruses tend to be highly host-specific and the papillomaviruses that infect companion birds are not known to infect humans or other unrelated species of birds.
Papillomas have been most frequently diagnosed in finches, waterfowl, cranes, herons and flamingos although the disease has also been confirmed in canaries and African grey parrots. Suspicious lesions have been identified in the skin of many types of psittacine birds.
Papillomas can take months to develop. The lesions can persist for months to years and then may spontaneously resolve. The predisposing factors for development of papillomas in companion birds are unknown.
What To Watch For
Diagnosis is unnecessary unless the papilloma causes discomfort or difficulty standing, moving or eating. Diagnosis is usually made from microscopic examination of sample tissue (biopsy) from the mass.
When necessary, papillomas can be removed with surgery or, in some cases, chemical cauterization. In mammals, autogenous vaccines are used but their effect in birds has been poorly documented.
Papillomas, or warts as they are commonly called, are caused when a papillomavirus infects the outer most cells of the skin. The clinical problems associated with warts are primarily associated with skin. Once the papillomavirus takes over a cell, it causes the cell to undergo cancerous changes resulting in a thickening of the skin and development of a mass.
While many papillomaviruses have a preference for the skin, in humans some papillomaviruses have been known to infect and cause cancerous changes in the mouth, gastrointestinal tract and reproductive tract. The papillomavirus associated with the formation of warts on the skin of birds is considered to be a type of benign tumor.
Papillomas of the skin caused by a papillomavirus should be differentiated from papillomatosis, which is a wart-like lesion that can occur on the surface of the cloaca or along the gastrointestinal tract in psittacine birds. Recent research suggests that papillomatosis is probably caused by a virus.
Papillomaviruses have been identified in a wide variety of animals, humans, many other mammals and birds. The most commonly affected species of birds include finches, waterfowl, cranes, herons and flamingos. Papillomaviruses tend to be highly host-specific and the papillomaviruses that infect companion birds are not known to infect humans or other unrelated species of birds. It is probable that other variants of this virus will be identified in psittacine birds.
Warts in birds are similar in appearance to those in people. The skin lesions associated with papillomavirus appear similar to those caused by some avian poxvirus. Although a virus has yet to be demonstrated, papilloma-like lesions have been diagnosed microscopically in association with proliferative growths originating from skin overlying the toes, uropygial gland, mandible, neck, wing, eyelids and beak commissure from various psittacine species. A herpesvirus has been documented in wart-like growths on the feet of cockatoos and macaws. It is not known if this herpesvirus causes these skin changes or merely replicates in the damaged skin cells.
The factors associated with papillomavirus transmission in birds are unconfirmed. It is probable that birds are exposed through direct contact with an infected bird or through contact with a contaminated surface (perch, enclosure, table, food bowls, etc). Papillomaviruses are considered to be relatively stable when outside of the host. Because the incubation period for papilloma development in birds is unknown, it is usually difficult to determine when, where, and how a bird may have been exposed to a papillomavirus. Cool, moist conditions and freezing will preserve the infectivity of most viruses.
Papilloma should be considered in any bird with a proliferative skin mass, and any type of skin mass that continues to grow should be evaluated by an avian veterinarian.
Confirming that a suspicious mass on the skin is a papilloma requires microscopic examination of a sample of tissue collected from the affected area. Confirmation that lesions with characteristic microscopic changes are caused by a papillomavirus requires electron microscopic demonstration of virus particles in affected cells.
Currently, there is no test that can be used to confirm that a bird does not have papilloma.
Generally, papillomas on the skin of birds do not need to be treated unless they are causing specific problems. Some lesions can be debilitating if they are damaged, allowing secondary infections to occur, if they inhibit a bird's ability to move or interfere with grasping or chewing food.
Mild lesions can be observed for changes that would necessitate their removal. Severe lesions can be removed surgically to make a bird more comfortable.
In some mammals, the use of autogenous vaccines, which are produced by grinding papillomas collected from the skin of an affected animal, have been shown to be effective in stimulating an immune response that results in cessation of warts. Autogenous vaccines have been used in some waterfowl and flamingos with mixed results. It has not been determined whether these vaccines would be effective in treating papillomavirus-induced skin lesions in companion birds.
Optimal treatment for your companion bird requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your bird does not rapidly improve.
There is currently no vaccine available to help prevent the unrestricted spread of papillomavirus in birds. Autogenous vaccines made from the affected tissues of birds may be used if a flock problem is occurring.