Several wild bunnies in Colorado have been spotted with strange “horns”.
Cottontail papilloma virus (CRPV) causes tumours to grow from the rabbit’s face.
Multiple sightings of infected rabbits have been reported to local news as the disease spreads in Fort Collins.
The increased number of infections is likely due to the summer weather, as CPRV is spread by tick, flea, and mosquito bites.
Susan Mansfield told 9NEWS about her encounter with one of the infected rabbits.
“It looks like it has black quills or black toothpicks sticking out all around his or her mouth.”
The horn-like growths are thought to be the inspiration for the jackalope, a mythical horned rabbit referenced in North American folklore.
They develop from warts and can be removed by veterinarians before they become malignant.
Mansfield said she was surprised to see the rabbit return after first spotting it a year earlier.
“I thought he would die off during the winter, but he didn’t. He came back a second year, and it grew.”
While the tumours are thought to be painless, diseased rabbits may starve if the growths are large enough to stop them eating.
Colorado Parks and Wildlife (CPW) doesn’t believe the virus can spread to humans or other animals, but has warned the public to keep their distance.
American virologist Richard E. Shope used CRPV as a model for the sexually transmitted human papillomavirus (HPV) in some of his research because the two viruses share several key characteristics.
This research led to the development of the HPV vaccine, which became available in 2006.