Fibromas are firm, nodular, fleshy masses attached to the skin. They are commonly described as warts. Fibromas vary in size from less than one inch to more than four inches in diameter, and they can be found anywhere on the deer's body, but are most common on the face, neck and forelegs. Fibromas are caused by papillomavirus.
It is not known exactly how the virus is spread but it is thought that it may be spread by direct contact between deer. The virus may also be spread by biting insects.
Fibromas only affects the skin of the deer and the only sign of this disease is the wart-like masses attached to the skin. Occasionally, a deer will be severely infected with multiple fibromas which interfere with the eyes or normal use of the legs, causing health problems for the deer.
Infected deer usually mount an immune response and the fibromas eventually disappear.
The virus does not affect people and fibromas cause no damage to the meat, which is safe to consume.