A further dose can be given at four weeks. This is a highly contagious, viral disease of the respiratory tract. The first sign which you are likely to notice is a harsh, dry cough which will last for 2-3 weeks and may well persist much longer. Initially there will be a clear discharge from the nostrils which later becomes thick and purulent. Equine FLU debilitates a horse or pony, leaving it susceptible to secondary infections.
Influenza can develop into bronchitis or bacterial pneumonia.
However, even when there are no complications from any secondary infections, the animal will need to be rested for at least 3 weeks and often considerably longer. An infected horse is itself a source of infection to others and it is important to make every effort to isolate infected animals. It is essential that your veterinary surgeon's advice is sought, not just at the onset of symptoms but also before restarting exercise. The only practical way to prevent infection with equine 'flu viruses is to ask the vet to vaccinate your horse or pony regularly. There are several 'flu vaccines available.