Equine Influenza

1
Equine InfluenzaFlu or two-year-old cough

• Highly contagious viral disease (Myxovirus
  influenza)
• Two strains of the virus (Equine A-1 and Equine
  A-2). Both produce clinically identical symptoms
  of the disease.
• Immunity produced following infection with one
  strain does not provide protection against the
  other.

2

• Can affect horses of all ages, however most often
  seen in young horses.
• Appears suddenly

3
Symptoms of Equine Influenza

• Elevated temperature (102o to 106oF,lasting 1 to
  6 days)
• Loss of appetite
• Respiratory distress
• Depression
• Muscular weakness and tremors are not uncommon
• Incubation period varies from 2 to 10 days

4

• In some horses there may be swelling of the lower
  surface and extremities accompanied by
  inflammation of the tendon sheaths.
• Watery nasal discharge that may become thick and
  yellowish colored.
• Lymph glands of the head and neck may become
  swollen, can mistake for strangles.

5

• Fatalities from flu are rare, provided horses are
  kept at complete rest and the disease does not
  become complicated by a secondary bacterial
  infection.
• Common secondary infections include rhinitis,
  laryginitis, pharyngitis, tracheitis, pneumonia
  and digestive disturbances.
• Prolonged pneumonia may affect the heart,liver
  and kidneys.

6
Treatment of Equine Influenza

• Neither antibiotics or sulfa drugs are effective
  against the virus, however they may help prevent
  secondary bacterial infection.
• Adequate rest both during and following the
  disease is essential. Failure to provide rest is
  responsible for the persistence of symptoms and
  chronic coughing (two-year-old cough).

7
Prevention of Equine Influenza

• All horse should be vaccinated (immunized).
• Immunization can be started as early as three
  months of age.
• Most programs require two doses initially
  followed by an annual booster.
• High risk horses repeatedly exposed at tracks or
  other equine events may be given a booster every
  six months.