"Anyone working with horses should be on the lookout and immediately report any suspected cases of Hendra virus infection over the coming months."
Common signs to look out for include respiratory distress, frothy nasal discharge, elevated body temperature (above 40 degrees C), and elevated heart rate.
However, it is important to realise there are no specific signs of infection.
"So far cases of Hendra infection have been restricted to Queensland and New South Wales, but there is potential for the disease wherever there are flying foxes," Smyth said.
Flying foxes, a native fruit bat, are known to be reservoirs for the disease, which can be passed on to horses and then on to humans.
The last two human fatalities have been horse veterinarians.
"Protective measures include placing feed and water under cover where possible, not placing feed and water under trees when flying foxes are in the area, not using feed that might attract flying foxes, such as fruit and vegetables, and, where possible, removing horses from fields where flying foxes are active, and fencing off trees where flying foxes roost."
The few cases of human Hendra virus infection have been the result of very close contact with horses infected with the virus. Body fluids or secretions from infected animals are likely to contain the virus.
"The risk can be greatly reduced by adopting good hygiene practices as a matter of routine and taking increased precautions around any sick horse," he said.
"It is also important to wash your hands with soap and water regularly before, during and after handling horses and minimise contact with your horse if it is unwell."
Since 1994, Hendra virus has been confirmed in 40 horses and seven humans. In these cases all horses either died or were destroyed and four of the people died.
The association urges Australian horse owners to contact their veterinarian immediately if they notice health problems in their horses or suspect they may be infected with Hendra virus.