Bovine Herpesvirus 1

VIRUSES HERPESVIRUSES

Antigenicity

• Two different viruses:
  • Infectious bovine rhinotracheitis (IBR): aerosol transfer
  • Infectrious Pustular Vulvovaginitis (IPV): venereal transfer

Pathogenesis

IBR:

• 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
• Dypsnoea, anorexia
• Rhinotracheitis that can develop into bronchopneumonia
• 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
• Generally high morbidity, low mortality, but up to 75% mortality if concurrent with BVDV, caused by meningo-encephalitis

IPV:

• Painful genital lesions
• Impaired reproductive performance
• Frequent micturition

Diagnosis

• Virus isolation and immunofluorescence

Control

• Vaccination:
  • Two live attenuated vaccines are available in the UK, one is temperature-sensitive
    • Both given intranasally
    • Neither protect against re-infection when given during clinical outbreak, but can lessen the severity of the disease
  • Inactivated vaccines: intranasal/intramuscular administration
    • gE deletion makes this a marker vaccine
    • ELISA for gE deletion can enable culling of carrier animals
• IPV has mostly been made obsolete by AI