Equine influenza (EI) is an acute, highly contagious viral disease which causes rapidly spreading outbreaks of respiratory disease in horses and other equine species such as donkeys. It is called an exotic disease, meaning that is not present in New Zealand and until recently had not been present in Australia. It is present in virtually all other countries apart from Iceland!

The main clinical signs of EI are a deep, dry, hacking cough, a watery nasal discharge that may become coloured and a sudden increase in temperature (39 degrees Celsius or higher).  Other signs can include depression, loss of appetite, laboured breathing, muscle pain and muscle stiffness.

EI is mainly spread by direct contact between horses, which is why horse movements are currently restricted in Australia. Humans can spread EI but only as physical carriers i.e. the virus can easily be spread on contaminated clothing, footwear, equipment or vehicles. Humans do not get infected. Transmission of EI to humans has never occurred during outbreaks of EI in horses.  EI is rarely fatal, but affected horses can take weeks to recover. In rare circumstances it can cause deaths in foals, very old animals or those already sick with other conditions. Just like with human flu, there are no specific treatments for the disease, only palliative care for sick animals. Affected horses will typically recover and no longer be infectious. This may take several weeks and so infected properties are quarantined for 30 days from the last signs of infection. Once an animal has recovered and sufficient time (30 days) has elapsed without symptoms it poses no risk to other horses.

Why is controlling the equine influenza outbreak in Australia important for us?

It would have a major impact on the horse industry if it were to become established in the horse population here. All horses would be permanently at risk of infection with subsequent impacts on competitive and domestic activities. The estimated cost of an outbreak which is controlled is NZ$53m and if the disease becomes established here the cost could be greater than NZ$200m. If Australia fails to control the disease it may only be a matter of time before it arrives here, with the volume of traffic of horses and horse-people across the Tasman.

To control the disease in Australia all infected properties are being placed under strict movement control to ensure that the affected animals do not travel and the disease does not spread. These conditions will be maintained until at least 30 days after the last signs were seen in affected horses. 

All horse movements within New South Wales and Queensland have been prohibited and all local events have been cancelled. It is a criminal offence at present to move a horse in NSW, punishable by a $44,000 fine and 12 months jail.  The restrictions are in place indefinitely at this time until all infected animals have been found. Only if horses do not move anywhere is there any chance of controlling the disease.  There are vaccines available in countries which have the disease but none are currently available for use in New Zealand because vaccination can complicate diagnosis of the disease. Australia still hopes to eradicate the infection so that permanent vaccination of horses will not be required over there either.

If Australia fails to control the disease and begins a nation-wide vaccination programme the New Zealand authorities may reconsider the possibility of allowing vaccination in New Zealand.  If you suspect you have a horse with equine influenza call your vet or the MAFBNZ emergency hotline 0800 80 99 66.

Neil Houston
Veterinary Associates Equine & Farm
123 Airfield Road
P O Box 21
Takanini
Auckland NZ
09 2998709