Herpesviridae

Introduction

Feline herpesvirus -1

• Feline viral rhinotracheitis in rhinitis
  • 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

Gammaherpesviridae

Alcephaline-1 Virus