JPC SYSTEMIC PATHOLOGY
ENDOCRINE SYSTEM
January 2022
R-V02 (NP)

Signalment (JPC# 1367008):  A bull

HISTORY:  None

HISTOPATHOLOGIC DESCRIPTION:  Prepuce:  Multifocally, 30% of the epidermis is eroded to ulcerated and the subjacent dermis is infiltrated by numerous viable and necrotic neutrophils, fewer lymphocytes, plasma cells, and macrophages admixed with eosinophilic cellular and basophilic karyhorrectic (necrotic) debris, hemorrhage, fibrin, and edema. Immediately adjacent to the ulcers, keratinocytes within the stratum spinosum are separated by increased clear space with prominent intercellular bridges (spongiosis), and are swollen up to 2 times normal size with pale eosinophilic, variably vacuolated cytoplasm (intracellular edema).  Few scattered nuclei within the epidermis and most often adjacent to the erosions/ulcerations contain irregular, round to oval, eosinophilic to amphophilic, 5-7 um diameter viral inclusion bodies that marginate the chromatin and either fill the nucleus or are rimmed by a clear halo.  Diffusely within the dermis, immediately subjacent to the dermoepidermal junction there are numerous perivascular lymphocytes and plasma cells. Multifocally away from the ulcers, neutrophils transmigrate the epidermis (exocytosis), dermal blood vessels are multifocally lined by plump, reactive endothelial cells and contain moderate numbers of transmigrating neutrophils, and dermal collagen is mildly separated by clear space (edema).

MORPHOLOGIC DIAGNOSIS:  Prepuce:  Posthitis, ulcerative, multifocal, subacute, moderate, with epithelial eosinophilic intranuclear viral inclusion bodies, breed unspecified, bovine.

ETIOLOGY:  Bovine herpesvirus-1

ETIOLOGIC DIAGNOSIS:  Herpesviral posthitis

GENERAL DISCUSSION:

• Alphaherpesvirus, DNA-virus; worldwide distribution
• BHV-1 causes infectious bovine rhinotracheitis (IBRV), infectious pustular vulvovaginitis (IPVV), and infectious balanoposthitis
• The different syndromes rarely occur simultaneously; caused by different subgroups:
  • Subgroup 1 – IBRV (more virulent)
  • Subgroup 2 – IPVV/balanoposthitis
  • Subgroup 3 - neurotropic
• All syndromes can result in abortion (up to 25% in naïve populations), typically between 5-8 months of gestation
• Terms:
  • Phallitis – inflammation of the penis
  • Balanitis – inflammation of the glans penis
  • Posthitis – inflammation of the prepuce
  • Phaloposthitis or balanoposthitis – inflammation of the penis and prepuce

PATHOGENESIS:

• Transmission: Venereal transmission through coitus or artificial insemination; nasal-genital transmission between cows has been postulated
• Latency: Lifelong latent infection with periodic virus shedding; sciatic ganglia are sites of latency in genital disease
• Recrudescence: Can be caused by stress (transport, parturition, etc.), corticosteroid administration, or superinfection by a new strain

TYPICAL CLINICAL FINDINGS:

• Painful urination, swelling and purulent preputial discharge with paraphimosis
• Reluctance or refusal to breed

TYPICAL GROSS FINDINGS:

• Penis and prepuce:
  • Early: Hyperemia and swelling of the penis and prepuce
  • Later (2-3 d): Pustules > 1-2 mm ulcers > small gray foci of necrosis of the penile epithelium
  • Lesions concentrated on the glans penis and prepuce
  • Edema of penis and prepuce in severe cases
• Uterus
  • Acute necrotizing endometritis possible, most often in the uterine body or caudal parts of uterine horns
• Fetus and placenta
  • Typically autolyzed which may mask lesions
  • 1-3mm diameter necrotic foci under liver capsule and/or surface of lung
  • Perivascular renal hemorrhages
  • Typically no gross placental lesions

TYPICAL LIGHT MICROSCOPIC FINDINGS:

• Penis and prepuce:
  • Epithelial necrosis with neutrophilic accumulation
  • Lymphocyte infiltration of the surrounding stroma
  • Transient appearance of intranuclear viral inclusion bodies in degenerating epithelial cells
• Uterus
  • When present, lesions range from mild focal lymphocytic endometritis to severe diffuse necrotizing metritis
• Fetus and placenta
  • Foci of necrosis with minimal cellular infiltrates in liver, adrenal gland, kidney, intestine, lymph node, lung, and spleen
  • Inclusion bodies may be difficult to discern in autolyzed specimens, may be found in adrenal glands around foci of necrosis
  • Necrotizing vasculitis consistently present in small vessels of placental villi

ADDITIONAL DIAGNOSTIC TESTS:

• Isolation or detection of virus through PCR or culture
• Serology with serum neutralizing titer
• ELISA

DIFFERENTIAL DIAGNOSES:  

• For balanoposthitis in bulls:
  • Granular venereal disease (bovine granular vulvovaginitis): Mycoplasma bovigenitalium
  • Ulcerative posthitis: Corynebacterium renale is the suspected etiology
  • Strongyloides papillosus
  • Traumatic injury secondarily infected with bacteria (e.g. Trueperella pyogenes, E. coli, Streptococcus, and Staphylococcus sp.)

COMPARATIVE PATHOLOGY:  

• BoHV-1 in other species:
  • Sheep, goats, and pigs: Can be infected by BoHV-1, but usually develop a mild upper respiratory infection, not balanoposthitis
• Infectious causes of balanoposthitis:
  • Canine: Canine herpesvirus causes inflammation at the base of the penis and the reflection of the prepuce but does not cause pustules or ulcers
  • Equine: Equine herpesvirus-3 (equine coital exanthema):  Ulcers have a predilection for the body rather than the glans of the penis
  • Goats: Caprine herpesvirus-1: Ulcerative balanoposthitis with acidophilic intranuclear viral inclusions; may progress to extensive suppurative and necrotizing balanoposthitis involving the glans, fornix, and entire urethral process; abortion in females with neutrophilic infiltrates in kidneys, brain, liver, adrenal glands, and lungs of aborted fetuses with intranuclear viral inclusion bodies in cells within/around the necrotic foci in kidneys and adrenal glands

REFERENCES:

1. Foster RA. Female reproductive system and mammae. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:1169-70, 1181.
2. Foster RA. Male reproductive system. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:1216.
3. Foster RA. Male genital system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 3. 6^th St. Louis, MO: Elsevier; 2016:506-507.
4. Schalfer DH, Foster RA. Female genital system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St. Louis, MO: Elsevier; 2016:433-435.

Click the slide to view.

---