This artificially coloured electron micrograph of Hendra virus is from the first identified case in Brisbane in 1994. © CSIRO
The Australian Horse Industry Council is pointing to recent research into the virus, which is carried by flying fox bat populations in Australia.
"The new information is that horses can be infected with Hendra virus for a couple of days before showing any clinical signs of being ill," the council said.
"During that time they can be excreting Hendra virus, which potentially can infect anybody who comes into contact with the infected horse."
The research showed that infected horses appear normal, but have increased heart rates and body temperatures before they become ill.
"It is essential that horse owners take appropriate steps to prevent access by horses to all areas where flying foxes congregate."
The council said the research had implications for horse owners or managers in other areas of Australia.
"Horses travel regularly from Queensland and northern New South Wales (where Hendra virus infections have been detected) to all parts of Australia.
"This means that horses from these areas must be isolated, observed and monitored closely for the first few days after arrival to ensure they remain healthy.
"If they are ill, then a veterinarian should be called and advised that the horse has recently arrived from an area where it is possible to have come into contact with flying foxes and Hendra virus.
"This enables the veterinarian and those in contact with the horse to take appropriate precautions to prevent them becoming exposed to Hendra virus when examining the horse and taking samples for laboratory analysis."
The council said the current outbreak of Hendra at a Queensland property, and recent cases of Strangles among horses in New South Wales, highlights the need for all horse owners to institute biosecurity measures.