The Shope papilloma parasite (SPV), also called cottontail mole papilloma virus or CRPV, is a highly pathogenic viral infection that infects many leporidians, causing rare, solid papillomavirulent lesions resembling horns, usually on or around the animal’s face. This infection is typically transmitted by contact with contaminated objects, particularly with the open cavity areas where animals bite their nails. The most common signs and symptoms include fever, generalized weakness, loss of appetite, mild to moderate pain and bleeding upon biting. Sometimes, leporidians may develop open wounds or abscesses at the site of infection. These sites can be identified by biopsy, CT scan, X-ray or surgery.
It is generally thought that Shope is caused by a strain of the Kappapillomaviruses family, although this remains unproven. The virus has recently been found to cause certain types of cancer in laboratory mice. An extravasated antibody is considered a high-risk factor for contracting Shope in case of infection. This is because antibodies released in response to the infection itself (or to any toxins produced by the infection) can provide a shield to help the body fight off infection. However, since these antibodies often attack healthy tissues, they can increase the risk of developing some cancers.
To date, Shope is thought to be caused by a strain of the Kappapillomaviruses family called CMLV. This group includes strains of Ehrlichia and Canine Mumps, as well as several members of the virus family named Archaeoplasmosis. The strain that causes Shope belongs to the second group, CMLV-A, and is thought to have been first discovered in Australia. The virus has been identified as a highly infective spore causing multiple organ system problems, including cervical cancer in women. Since its discovery, Shope has become one of the most common strains of the CMLV family, with the virus causing many different clinical symptoms in dogs. Shope is also associated with kidney problems, including necrosis and kidney failure.
In dogs, Shope infections are often associated with external parasites like lice or fleas, or infections caused by bacteria. Because Shope is a transovarian viral infection, it is typically associated with dogs that are born with birth defects involving the epithelial cells of the vulva. Because the virus spreads easily through air or water, Shope has also been associated with infestation of newborn kittens in pregnant mothers. The virus has also been implicated in the spread of cancer cells in laboratory animals like rabbits and hamsters.
The only clinical sign reported in humans is the presence of lesions, usually flat and red, that appear on the inside of the mouth. These lesions may ooze and sizzle, and may be painless. Shope virus infection of domestic rabbits has been associated with death due to asphyxiation, and with reduced weight loss in sick rabbits. In most cases, Shope appears to be transmitted to the ferret via direct contact with contaminated feces. Young adult male rabbits are particularly vulnerable to Shope virus infections because they lack epithelial layers at the base of their skull.
Recently, molecular biologists have found evidence that suggests a causal relationship between Shope and cervical cancer in humans. Methylsulfonylmethane, a compound commonly used in methicillin and other antibiotics, has been shown to cause genetic changes in cells. If Shope is present in a patient’s blood, it can cause dysplasia, a condition in which the developing tissue swells and grows abnormally. Although this isn’t common, and the changes often only affect the size of a single tissue, dysplasia can lead to cervical cancer in susceptible individuals.