DISEASE SUMMARY PAGE

Oral Papillomatosis in Rabbits

Summary Information
Diseases / List of Viral Diseases / Disease summary
Alternative Names  
Disease Agents
Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s) --
General Description
  • This is a transmissible disease. (B600.9.w9)
  • Young rabbits are most susceptible. (B600.9.w9)
  • Rabbit oral papillomas are a benign disease and have not been known to undergo carcinomatous transformation. (B600.9.w9; B602.16.w16)
  • The domestic rabbit, Oryctolagus cuniculus, is the natural host of this virus but experimental infection has been successful in cottontails, Sylvilagus- (Genus), and hamsters. (B209.11.w11)
Pathogenesis
  • The papillomas grow slowly over six to nine months. (B600.9.w9)
  • The rabbit then becomes immune at which point the papilloma's base becomes inflamed which leads to the sloughing of the tumour, formation of an ulcer and then finally re-epithelialisation. (B600.9.w9)
  • Once recovered, rabbits appear resistant to repeated further infection. (B603.3.w3, J4.157.w2)
  • Usually the papillomas grow for about a month, then decrease in size. (J494.77.w1) 
    • The papillomas may last only a few weeks. (B602.16.w16)
    • Persistence as long as 400 days has been noted occasionally. (J494.77.w1)
    • Persistence noted to 94 and 100 weeks. (J83.6.w2)
Incubation 
  • Following inoculation, 6-38 days (average 14 days). (J494.77.w1)
Clinical signs
  • Small, white, wart-like growths on the ventral tongue and rarely elsewhere on the oral mucosa (e.g. on the dental pad behind the incisors). (B600.9.w9; B602.16.w16)
    • Early lesions are dome-shaped, sessile; they later become rugose or pedunculated (cauliflower like) and may reach e.g. 3 mm high. (B602.16.w16, J4.157.w2, J83.6.w2)
      • In an outbreak in the UK, lesions were pink, mainly on the lower gum, reached 10 mm high and lasted as long as 94 - 100 weeks. (J83.6.w2)
    • Lesions slough to leave an ulcer, which then heals. (J4.157.w2)
    • Lesions are typically one to three millimetres wide but can exceed four to five millimetres at their greatest dimension. (B602.16.w16, J4.157.w2)
  • Note: In a single case, persistent conjunctival papillomas were seen due to oral papillomavirus infection in a Flemish Giant rabbit in new Zealand. (J501.46.w1)
Pathology

Histopathology

  • Hyperkeratosis and parakeratosis, with cytopaslmic swelling and vacuolation of cells in the stratum spinosum, and intranuclear inclusions in more superficial cells. (J83.6.w2)
  • Folded, thickened epithelium on branching papillae. Cells in early lesions appear normal, but in later lesions cytoplasm of cells contains vacuoles, increasing in size, and cells develop an irregular polyhedral shape; mitotic figures are visible in cells in the basal layer. Intranuclear inclusions may be found in as many as 10% of cells (but were not found in experimentally infected Sylvilagus sp. rabbits). There is a sharp demarcation from normal tissue. (J494.77.w1)
  • Electron microscopy: Papopva-like viruses. (J83.6.w2)
Susceptibility/Transmission
  • Oral secretions that contain sloughed cells from the warts. (B600.16.w16)
  • Papilloma homogenate has been shown to induce papillomas on the ventral surface of the tongues of rabbits, but not on the conjunctiva or vulva. It has also been shown to induce fibromas in neonatal hamsters. (B602.16.w16, J13.46.w2)
  • Transmitted from dam to kits, probably if the kits have any small break in the oral mucosa. (J494.77.w1)
  • Cottontail rabbits (Sylvilagus sp.), Lepus californicus - Black-tailed Jackrabbit and Lepus americanus - Snowshoe hare are susceptible to experimental infection. (J494.77.w1)
  • Usually seen in rabbits under two years of age. (J213.8.w2)
  • Inoculation of the penile mucosal surface has successfully produced lesions in New Zealand White rabbits. (J80.72.w1)
Diagnosis
  • Biopsy and histopathological examination for definitive diagnosis. (J213.8.w2)
  • Papillomavirus structural antigens can be detected in the stratum spinosum (peroxidase-antiperoxidase technique). (J13.46.w2)
Treatment
  • Generally not required. (B603.3.w3)
  • If necessary, supportive treatment for secondary bacterial infection or obvious discomfort. (J213.8.w2)

Prevention

  • A peptide vaccine has been produced and shown effective experimentally. (J80.76.w3)
Further Information Morbidity:
  • In one study, 31% of 51 New Zealand White rabbits from two local sources were found to have oral papillomas. (J213.8.w2, J13.46.w2)
  • Lesions were found in 118/722 domestic rabbits in one study (J494.77.w1) and 35/210 (all 2 - 18 months old) in another. (J4.157.w2)
  • No lesions were seen in more than 300 wild rabbits examined. (J494.77.w1)
  • Natural infections are reported sporadically in domestic rabbits, e.g. as an incidental necropsy finding. (J213.8.w2)

Geographic occurence

  • Reported from North America, Europe (Netherlands, UK), Mexico and New Zealand. (J13.46.w2, J83.6.w2, J495.31.w1, J501.46.w1)
Associated Techniques
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Host taxa groups /species
Disease Author Nikki Fox BVSc MRCVS (V.w103); Debra Bourne MA VetMB PhD MRCVS (V.w5)

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