Equine Influenza

EQUINE INFLUENZA

Definition

  • It is an infectious respiratory disease of horses characterized by mild fever and a severe persistent cough

Etiology

  • Type A influenza virus
  • First isolated and identified in 1958 in Czechloslovokia (A/Equi 1 Serotype)
  • Second serotype -1963 in Miami, USA (A/ Equi2)
  • The virus is of two serotypes based on antigenic differences in their haemagglutination
  • First recorded in India in 1987

Susceptibility

  • All age groups including newborn foals of 2-6 months age
  • Two years and younger horses are highly susceptible

Mortality

  • 0.1%

Morbidity

  • 80-100%

Transmission

  • Droplet inhalation
  • Fomites-Direct contact

Pathogenesis

  • Inhalation of virus, multiplies in epithelial cells of upper respiratory tract causes erythema, oedema and focal erosions
  • Viraemia is brief and mild
  • Deciliation causes secondary bacterial infection and complicate the condition

Clinical signs

  • Incubation period -2-3 days
  • Fever (1010-1060F)
  • Cough –Dry to moist for 1-3 weeks
  • Watery nasal discharge
  • Depression
  • Reluctance to move
  • Anorexia
  • Deaths in young foals due to pneumonia

Lesions

  • Erosions in mucosa of nose, pharynx, larynx, trachea
  • Lungs-peribronchitis , periarteritis, broncho pneumonia

Diagnosis

  • Serological tests- Complement fixation test
  • Haemagglutination test
  • Serum neutralization
  • ELISA
  • Identification of viral antigen by immunostaining

Differential diagnosis

  • Equine rhino pneumonitis affects only young horses
  • Equine viral arteritis produces oedema of limbs
  • Colic
  • Diarrhoea
  • Conjunctivitis
  • Photophobia
  • Abortion
Last modified: Saturday, 17 December 2011, 10:05 AM