Research Continuing on Equine Hendra Vaccine

Biosecurity Queensland shared new advice regarding the equine hendra virus vaccine with Australian horse owners in a May 13 news release.

Chief Biosecurity Officer Jim Thompson, BVSc, MACVSc, said recent data evaluated by the Australian Pesticides and Veterinary Medicines Authority showed that the vaccine offered protection to horses for a period of up to six months.

"Research is continuing to determine if the vaccine will provide protection against hendra virus for up to 12 months," he said. "Changes have also been made around the timing of the second dose. When the vaccine was first made available late last year there were strict requirements on the timing of the second vaccination. Further research means that the second dose can now be administered anytime between three to six weeks after the first dose.

"Vaccination is the single most effective way to reduce the risk of hendra virus infection in horses and Biosecurity Queensland encourages horse owners to have their horses vaccinated," he continued. "However horse owners shouldn't become complacent, even after vaccination. We still recommend the use of good personal hygiene and biosecurity measures when working with horses, regardless of their vaccination status."

Horse owners should discuss vaccination with their veterinarian, and they should familiarize themselves with other measures to reduce the risk of hendra virus infection. Steps to reduce the risk of hendra virus include:

  • Talk to your veterinarian about vaccinating your horse against hendra virus,
  • Horse feed and water containers should be removed from under trees. If possible, place feed and water containers under a shelter.
  • Owners should inspect and identify flowering/fruiting trees on their property. Horses should be removed from paddocks where flowering/fruiting trees are attracting flying foxes (the species of bat known to play a role in transmitting hendra to horses). Horses should be returned only after the trees have stopped flowering/fruiting and the flying foxes have gone. If horses cannot be removed from the paddock, consider fencing (temporary or permanent) to restrict access to flowering/ fruiting trees. Clean up any fruit debris underneath the trees before returning horses.
  • Temporarily remove your horses during times of peak flying fox activity (usually at dusk and during the night).
  • Ensure that sick horses are isolated from other horses, people, and animals until a veterinarian's opinion is obtained.
  • If a horse falls ill and there is more than one horse on your property, handle unaffected horses first and then only handle sick horses after taking appropriate precautions.
  • Make sure gear exposed to any body fluids from horses is cleaned and disinfected before it is used on another horse. This includes halters, lead ropes, and twitches. Talk to your veterinarian about which cleaning agents and disinfectants to use.
  • When cleaning contaminated equipment from a sick horse, wear gloves, cover any cuts or grazes, and wash your hands thoroughly afterwards.
  • It is essential that horse owners practice good biosecurity and not travel with, work on, or take sick horses to other properties or equestrian events. Do not allow visiting horse professionals (e.g. farriers), aside from veterinarians, to work on sick horses.
  • Seek veterinary advice before bringing any sick horse onto your property.

Hendra virus has been known to yield numerous clinical signs in horses including respiratory distress, frothy nasal discharge, elevated body temperature (above 40°C, or 104°F), and elevated heart rate; however, authorities caution that hendra infection does not have specific signs. The disease is zoonotic, meaning it can be transmitted from horses to humans, and as proved deadly for several humans exposed to sick horses in the past.

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