Horse flu is an infectious disease and can be passed very easily from one horse to another. As the virus replicates in the nose, throat and windpipe it is spread via aerosols when the horse breathes, coughs or sneezes.
The virus can also be passed on by direct contact and by handlers, so good hygiene is very important.
When horses are in close contact, flu can spread extremely quickly. Shows or drag hunts where horses come together in large groups and are under stress from travelling or competing can provide the perfect environment for the virus to spread. For this reason outbreaks of flu are often traced back to such events.
Any horse with a compromised immune system, either due to age, stress or illness, for example Cushings disease or COPD, will be at higher risk of horse flu, click here for more information.