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EQUINE INFLUENZA (EI): Frequently Asked Questions

WHAT IS EQUINE INFLUENZA?
Equine Influenza (EI) is an exotic viral disease of horses. All Equidae (ie horses, donkeys, mules and zebras) are susceptible and the features of the disease in these animals are similar.


WHERE DOES EI OCCUR?
The disease occurs widely throughout the world. Australia and New Zealand have been the only two countries with significant horse populations free of the disease. The recent EI outbreak in Australia is of great concern to both our industries.

HOW IS EI SPREAD?
EI is a highly contagious disease that is transmitted directly from acutely infected to susceptible horses. Horses with the disease remain infectious for up to 7-10 days. No carrier state (where an animal, which is not itself sick, harbors an infective organism that may cause disease in those to which the organism is transmitted) has been demonstrated.

The virus is present in the aerosol created by coughing horses and spread over 32 metres has been recorded. Longer-distance aerosol or windblown transmission has been suggested as a possibility. Transmission by people, contaminated vehicles and equipment has contributed to the rapid and widespread distribution of the disease in many outbreaks.

The disease has a very short incubation period (ie time from infection to symptoms) of 1-5 days and clinical signs usually resolve in 1-3 weeks.

WHAT ARE THE SYMPTOMS OF EI?
The disease starts with a high fever (often 40-41 degrees C). Animals are often depressed, off their food, stiff and reluctant to move. The predominant clinical sign is a dry, unproductive, explosive cough.


Nasal discharge may be absent or clear in the early part of the disease, later becoming mucoid (ie like mucus, slimy and sticky). While a large number of horses may become infected, especially in a very naive population such as ours, only a small number will die, usually due to secondary complications.


For more information about EI please refer to:
Keeping Exotic Horse Diseases out of New Zealand - written Dr Brian Goulden & Dr Trish Pearce, published by the NZ Equine Health Association in 2001, and distributed as a free booklet throughout the New Zealand equine industry.
Copies of the booklet are available from the NZTBA.

WHAT SHOULD I DO NOW?
If you are in charge of horses that have arrived from Australia since 1 August we urge you to contact your local veterinary surgeon, or call the:

MAF BIOSECURITY HOTLINE
0800 80 99 66


Horses that have arrived from Australia very recently should be kept isolated and their status checked often. Generally the clinical signs are sufficient to establish a diagnosis, but this needs to be confirmed with laboratory tests.

WHAT MEASURES ARE BEING TAKEN TO PREVENT THE SPREAD OF EI TO NEW ZEALAND?
MAF Biosecurity has stopped all horse imports from Australia to New Zealand from midday on Saturday 25 August. Officials are now tracing horses recently imported from Australia and arranging for them to be examined to ensure they are not infected with EI.


Should the disease arrive in New Zealand we will be faced with undertaking the same measures as Australia – that is, stopping all horse movements for at least 30 days. The effectiveness of those measures may well depend on how quickly EI is diagnosed, so maintaining a close watch on all horses is vital.

Bruce Graham
Chairman
NZ Equine Health Association
Mob: 021 351 168



- NZ Equine Health Association