Herpesviridae

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Introduction

  • In skin infections
    • Bovine herpes virus 1, 2 4
    • Equine herpes virus 3
    • Feline herpes virus 1

Feline herpesvirus -1

  • Feline viral rhinotracheitis in rhinitis, see respiratory infections
    • One of the causes of Feline viral rhinotracheitis
      • Viruses and bacteria are involved in the complex. The most frequent aetiologic agent is FHV-1, and less frequently feline calicivirus and/or Chlamydophia psittaci (NB: previously called Chlamydia psittaci var felis)
      • All three agents infect URT respiratory epithelium, although FHV-1 has the highest affinity for this epithelium
      • Feline calicivirus more frequently infects the oral mucosa -> ulcerative stomatitis
      • C.psittaci more frequently infects the conjunctival epithelium -> chronic conjunctivitis
      • Infection of the respiratory epithelium by FHV-1 results in a typical neutrophilic rhinitis with intraepitheial intranuclear eosinophilic inclusion bodies, with expected clinical signs
      • Resolution of clinical signs usually occurs by 7-14 days.
      • FHV-1 remains latent in the trigeminal ganglion, and can reactivate at times of stress. Can infect the cornea -> ulcerative keratitis.
      • Occasional mortality in kitten or immunocompromised animals usually associated with secondary bacterial infection.


Bovine herpesvirus -1

  • Bovine herpesvirus - 1 (Infectious bovine rhinotracheitis virus) contributes to undifferentiated neonatal calf diarrhoea, a mixed viral enteritis in calves; and rhinitis
  • Causes Infectious bovine rhinotracheitis (IBR)
  • Highly infectious URT disease of cattle
  • High morbidity, low mortality
  • Aerosol transmission - requires close contact between animals
  • BHV-1 infects the respiratory mucosal epithelial cells (intranuclear inclusion eosinophilic inclusion bodies)from nasal mucosa down to bronchioles
    • leading to neutrophilic inflammation of varying severity.... serous -> catarrhal -> purulent nasal discharge, sneezing, coughing.
    • with secondary bacterial infection (eg: Pasturella spp., Mycoplasma spp., Fusobacterium necrophorum) can lead to fibrinous to necrotizing inflammation; mucosal sloughing, ulceration... pyrexia, dyspnoea ... inhalation pneumonia... death.
  • Clinical signs include coughing, discharge, lacrimation, and increased respiratory rate.
  • Clinical disease most severe in young calves - can develop mucosal ulcerative lesions in the oesophagus and forestomachs and viraemia with multiorgan infection.
  • Cause of abortion >5 months of gestation

Inclusion body rhinitis (porcine cytomegalovirus)

  • Cytomegaloviruses
    • Porcine cytomegalovirus
      • Causes Inclusion body rhinitis
        • Disease of suckling piglets 1-5 wks of age
        • Clinical signs: those associated with acute/subacute rhinitis (ie: serous nasal discharge, progressing to catarrhal or purulent discharge with time and secondary bacterial infections; sneezing; pyrexia)
        • Morbitity high, mortality low
        • Histology: large basophilic intranuclear inclusion bodies in the nasal and sinus respiratory epithelium with lymphocytic infiltration of the mucosa.
        • Can develop viraemic stage, with inclusions in other organs eg: renal tubular epithelium. Piglets can die during this phase.

Alphaherpesviridae

Betaherpesviridae

Gammaherpesviridae

Alcephaline-1 Virus