EQUINE INFLUENZA

EQUINE INFLUENZA

Equine influenza occurs as an epizootic, viral disease characterised by a tracheobronchitis in adult horses and a primary viral pneumonia in foals. Horses of all ages are susceptible but infection is most common in young (<3>
INCIDENCE
Worldwide occurrence as a major disease of economic importance. Extensive use of killed vaccines has reduced the severity of clinical disease and degree of viral shedding but when new antigenic variants emerge, explosive outbreaks of disease can occur.
Large amounts of virus are aerosolised due to the frequent cough. Short incubation period (1-3 days) with viral shedding for about 10 days. Rapid transmission of virus over long distances make isolation virtually impossible
CLINICAL SIGNS

- Cough - sudden onset; group affected; harsh and dry
- fever, dullness, lethargy, anorexia
- bilateral, serous or mucopurulent nasal discharge
- increased respiratory rate and harsh respiratory sounds
- ± conjunctivitis/muscle stiffness/limb oedema.
Signs are less severe in vaccinated animals. Rare complications occur including bacterial bronchopneumonia.
DIAGNOSIS
Based on history and clinical signs, virus isolation form nasopharyngeal swabs and paired serology samples
TREATMENT

Rest, minimum 3 weeks.
Reduce environmental dust/moulds.
antibiotics prophylaxis.
antiflammatories to reduce fever and muscle stiffness.
+/-bronchodilators and mucolytics to ease respiration.
CONTROL
Outbreak

virtually impossible, aerosol transmission over hundreds of yards.
strict rest and isolation of affected cases.
cease training of susceptible in contacts.
vaccination of healthy in contacts.
Vaccination should be carried out, firstly with 2 doses 3-6wks apart then 6mth booster followed by annual boosters