What Causes Warts?
Warts are caused by a virus known
as papillomavirus. There are many different types of
papillomavirus - some of which only affect one species of animals, and
others that may effect more than one species. These viruses
are named according to the species that they affect: for example bovine
papillomavirus affects cattle while equine papillomavirus mainly
affects horses. Within each species, there may also be different
types of the virus: for example there are 6 types of bovine
papillomavirus that are distinctive according to different proteins
associated with the virus as well as the effects that they may cause in
the animal. Warts are generally thought to be a benign condition
when they develop, but are contagious between animals that are
susceptible to the same virus.
Transmission of Warts
Papillomavirus is spread between animals by direct contact of wart
material from an infected animal getting into a break in the skin of an
uninfected animal. It is also possible that the virus can live
inside wart material that is on an inanimate object such as a
scratching post, brushes, milkers, etc. and then be transmitted onto
the skin of an uninfected animal. It is important to realize that
infection only occurs when the virus can get into some kind of flaw or
break in the skin.
Who Gets Warts?
Any animal runs the risk of getting papillomavirus and developing
warts, but the risk is generally increased in young animals (who have a
poorly developed immune system), animals that are crowded in close
quarters with infected animals (this increases the likelihood of
transmission between animals) and animals that are sick or stressed
(thus having an already decreased ability for the immune system to
respond properly). Once an animal has been infected with
papillomavirus, it can take several weeks to months before any warts
appear. During this time the virus is infecting cells,
replicating, and infecting other cells in the area.
Treatment/Duration of Infection
Warts caused by papillomavirus are considered to be self-limiting,
meaning that they are benign and generally disapear on their own once
the immune response of the animal has taken control of the
situation. The duration of infection varies according to the
animal species affected.. If treatment is required, the options
are fairly limited to cryosurgery or surgical removal. See pages
on individual animal species for more information.