Introduction

Classification

Taxonomy

• Order: Spirochetalis.
• Family: Spirochetaceae.
• Genus: Treponema.
• Species: cuniculi or paraluis-cuniculi.

Etymology

• Gk: trepein - turn + Gk: nema - thread.
• L: cuniculi - rabbit, underground passage.

Active Forms

Clinical Effects

Epidemiology

Habitat

• Does not survive outside the host.

Transmission

• Venereal.
• Direct contact - affected does can infect kits at birth or via the milk.
• Vertical transmission commonly occurs as kits are infected from the birth canal.

Pathological effects

• Humoral antibodies can be detected in exposed and infected rabbits.
• Infection stimulates a polymorphonuclear cell response, then infiltration of plasma cells and macrophages.
• Causes venereal spirochetosis of rabbits.
• Lesions are usually limited to vulval or preputial skin and appear as papules, ulcers or hyperkeratosis.
• Lesions begin as areas of hyperemia and edema and progress to large papillary nodules that can become crusty.
• Lesions may also occur on the nose, lips, chin, face, eyelids, ears and paws, due to the social and grooming habits of the rabbit. 
• Spirochetemia has been reported.

Other Host Effects

• Subclinical infection is possible, with overt disease precipitated by stress or immunosuppression.

Control

Control via animal

• Often self-limiting.
• Treponemas are susceptible to antibiotics.
• May be eliminated from a colony by selective breeding of virgin females.
• Also consider quarantine of new animals and possible serological testing of new animals during quarantine.

Control via chemotherapies

• Penicillin Penicillin is the treatment of choice - usually given in the form of three long-acting injections given subcutaneously a week apart:
  • Dose rates vary widely, but general 42-84 mg/kg penicillin weekly for 3 treatments.
  • Long-acting amoxicillin may also be used via the same regime.
  • Monitor for dysbiosis during treatment and provide a good quality high fiber diet and probiotic.
• Tetracycline Tetracycline and chloramphenicol Chloramphenicol are also effective.
• Treat all in contact animals.
• Analgesia Analgesia should also be provided.

Control via environment

• Does not survive for long away from the host.

Other countermeasures

• Selective breeding of virgin females may be able to eliminate spirochetosis from a colony.

Diagnosis

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.
• Scarff D (2008) Skin diseases of pet rabbits. UK Vet: Companion Animal 13 (2), 66-75 VetMedResource.
• Centurion-Lara A, Castro C, Castillo R et al (1998) The flanking region sequences of the 15-kDa lipoprotein gene differentiate pathogenic treponemes. J Infect Dis 177 (4), 1036-1040 PubMed.
• DiGiacomo R F, Talburt C D, Lukehart S A et al (1983) Treponema paraluis-cuniculi infection in a commercial rabbitry: epidemiology and serodiagnosis. Lab Anim Sci 33 (6), 562-565 PubMed.
• Cunliffe-Beamer T L & Fox R R (1981) Venereal spirochetosis of rabbits: description and diagnosis. Lab Anim Sci 31 (4), 366-371 PubMed.

Other sources of information

• Varga M (2014) Skin Disease. In: Textbook of Rabbit Medicine. 2nd edn. Butterworth-Heinemann, Oxford. pp 271-302.
• Meredith A (2006) Skin Diseases and Treatment of Rabbits. In: Skin Diseases of Exotic Pets. Eds: Patterson S. Blackwell Publishing. pp 288-311.