JPC SYSTEMIC PATHOLOGY
INTEGUMENTARY SYSTEM
August 2019
I-B07

Signalment (JPC# 2155783):  Female rabbit (Oryctolagus cuniculus)

HISTORY:  Genital lesion

HISTOPATHOLOGIC DESCRIPTION: Mucocutaneous junction, vulva (2 sections): Diffusely the epidermis is hyperplastic, thickened up to 3 times normal, characterized by acanthosis, anastomosing rete ridges, intercellular clear spaces with prominent intercellular bridging (spongiosis), and intracellular edema.  There are multifocal erosions and ulcerations with replacement by a serocellular crust composed of necrotic cellular and karyorrhectic debris admixed with serum, numerous degenerate heterophils, lymphocytes, and variably sized colonies of 2 um diameter basophilic cocci.  Within the adjacent epithelium there is ortho- and rare parakeratotic hyperkeratosis.  The superficial dermis is infiltrated by moderate numbers of macrophages, heterophils, and fewer lymphocytes and plasma cells that surround adnexa and blood vessels, transmigrate the epidermis and follicular epithelium (exocytosis), and infiltrate follicular lumens (folliculitis).  Hair follicles are multifocally dilated and filled with lamellations of keratin.  Multifocally within the superficial dermis there is hemorrhage, fibrin, and increased clear spaces and ectatic lymphatics (edema). The inflammation extends into the deep dermis and panniculus carnosus muscle, surrounding, separating, and individualizing skeletal myocytes which are often shrunken and hypereosinophilic (atrophy).

MORPHOLOGIC DIAGNOSIS:  Mucocutaneous junction (vulva):  Dermatitis and folliculitis, suppurative and lymphoplasmacytic, diffuse, moderate, with epidermal hyperplasia, orthokeratosis, ulceration, and superficial mixed population of bacteria, breed not specified, lagomorph.

ETIOLOGIC DIAGNOSIS: Cutaneous treponemiasis

CAUSE: Treponema paraluiscuniculi (formerly T. cuniculi)

CONDITION:  Rabbit syphilis

SYNONYMS:  Venereal spirochetosis, vent disease, treponematosis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES: 

  1. Angell J, Clegg S, Sullivan L, et al. In vitro susceptibility of contagious ovine digital dermatitis associated Treponema spp. isolates to antimicrobial agents in the UK. Vet Dermatol. 2015;26(6):484 e115. 
  2. Angell J, Crosby-Durrani H, Duncan J et al. Histopathoological characterization of the lesions of contagious ovine digital dermatitis and immunolabelling of Treponema-like organisms. J Comp Pathol. 2015;153(4):212-226.
  3. Barthold SW, Griffey SM, Percy DH. Rabbit. In: Pathology of Laboratory Rodents and Rabbits, 4th ed., Ames, IA: John Wiley & Sons, Inc.; 2016:287.
  4. Clegg S, Crosby-Durrani H, Bell J, et al. Detection and isolation of digital dermatitis treponemes from bovine pressure sores. J Comp Pathol. 2016;154:273-282.
  5. Crosby-Durrani H, Clegg S, Singer E, et al. Severe foot lesions in dairy goats associated with digital dermatitis treponemes. J Comp Pathol. 2016;154:283-296.
  6. DeLong D, Manning P. Bacterial diseases. In: Manning PJ, Ringler DH, Newcomer CE, eds. The Biology of the Laboratory Rabbit. 2nd ed. San Diego, CA: Academic Press; 1994:151-154.
  7. Frössling J, Rosander, A, et al. Detection of Treponema phagedenis–like antibodies in serum and bulk milk from cows with and without digital dermatitis. J Vet Diagn Invest. 2018;30(1): 86–92.
  8. Hans S, Mansfield KG, et al. Treponeme-Associated Hoof Disease of Free-Ranging Elk ( Cervus elaphus) in Southwestern Washington State, USA. Vet Pathol. 2019;56(1):118-132.
  9. Klaphake E, Paul-Murphy J. Disorders of the reproductive and urinary systems. In: Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 3rd ed., St. Louis, MO: Saunders; 2012:222-223.
  10. Knauf S, Batamuzi E, Mlengeya T et al. Treponema infection associated with genital ulceration in wild baboons. Vet Pathol. 2012;49:292-303.
  11. Maboni G, Frosth S, Aspan A. Ovine footrot: new insights into bacterial colonization. Vet Rec. 2016;17:pii: vetrec-2015-103610.
  12. Njaa BL. The ear. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. Louis, MO: Elsevier; 2017: 1259.


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