E208
Equine Influenza

Clinical Signs: An infected animal starts with a fever, has nasal and eye discharge may be coughing, and stops eating. Signs begin 18 hours to 5 days after the initial infection. Some animals show stiffness, limb swelling, and pneumonia. Most horses recover within 2-3 weeks, unless complications arise due to bacterial infections or problems with heaves.

Disease Transmission: These viruses can be transmitted from one animal to another by direct contact, nasal secretions, contaminated buckets, feeders, halters, and other equipment.

Diagnosis: Based on clinical signs alone, it is difficult to tell the difference between an equine influenza infection, equine herpes, or viral arteritis. However, it is possible to isolate the influenza virus using matter collected on a nasal swab and in transtracheal washes. Blood from infected animals can also be used to identify titers specific for influenza.

Treatment: It is important to understand that treatment of viral infections involves treating the symptoms and not killing the organism. Treatment for the respiratory problems of this disease include the following:

1. Strict rest (3 weeks).
2. Keeping the animal out of dry, dusty, or stressful environments.
3. Non-steroidal anti-inflammatory drugs (bute or Banamine).
4. A broncho-dilater (Ventipulmin).
5. Possible antibiotics for secondary bacterial infections.

Prevention: Vaccination programs are the best prevention. See the vaccination schedule recommendations on page A905. Isolating animals when they enter a new location for 3-4 weeks will also aid in preventing disease transmission.