Hendra Virus: Protect Horses to Protect Humans

Hendra Virus: Protect Horses to Protect Humans

Keep horses' feed and water bins away from areas in which flying foxes roost to help prevent Hendra virus spread.

Photo: iStock

Hendra virus is bad news. It’s deadly for horses, deadly for humans, and can be passed from sick horse to human caregiver. As of now, Hendra has only been identified in Australia, and researchers there are working to find the best ways to prevent its spread.

Flying foxes, a member of the bat family, are a native Australian species. This protected bat is an important pollinator species, but it carries a potentially deadly disease called the Hendra (HeV) virus. To date, no human has directly contracted the virus from contact with a flying fox, but people can (and have) become infected through direct exposure to infected horses’ bodily fluids.

Although the exact route of transmission to horses has not been confirmed, researchers believe it to be from flying fox feces, placental fluids, or other bodily fluids. “It is thought that horses grazing contaminated pasture or feeding from contaminated feed or water bins can contract the virus,” said Sarah-Jane Wilson, BVSc, MVPHMgt, PhD, of the University of Sydney Faculty of Veterinary Science, in Camden, New South Wales, Australia.

The majority of horses that contract the disease have died, and the mortality rate in humans is 50%. “Complications of the disease in humans can include infections of the lungs or brain—severe cases have caused pneumonia and encephalitis,” she said.

To reduce the spread of HeV from flying foxes to humans, Wilson recommended that owners have their horses vaccinated. The vaccination, an initial two-dose protocol followed by a booster every six months, is the preferred method of preventing infection in horses. “It protects the horses, therefore protecting the humans,” Wilson added.

A regular vaccination schedule is also an economic solution. “The flying foxes are a protected species in Queensland, so you can only destroy them or interfere with their habitats under a strict mitigation permit, which limits the methods for controlling them,” she explained. Their habitats are widely dispersed throughout South East Queensland, often in areas where horses are housed or grazed.

The Hendra vaccine is widely available from almost all equine veterinarians and many mixed practice veterinarians in Australia. In addition to vaccination, Wilson offered several management strategies to reduce infection risk in horses:

  • Keep feed and water bins away from flying fox roosts;
  • Fence off the areas under trees or roosts;
  • Stable horses at night when flying foxes are active; and
  • Avoid planting fruit trees or native trees in pastures, which attract flying foxes.

Hendra is one of many diseases that is preventable through vaccination and is of paramount importance to the owners, handlers, and people treating the horses, Wilson said. “Being aware of sound biosecurity practices that relate to your horse is the gold star for all horse owners,” she concluded.

The study, “Intangible and Economic Impacts of Hendra Virus Prevention Strategies,” was published in Zoonoses Public Health

Editor's Note: This article was updated on Jan. 19 to include the proper recommended vaccination schedule.

About the Author

Katie Navarra

Katie Navarra has worked as a freelance writer since 2001. A lifelong horse lover, she owns and enjoys competing a dun Quarter Horse mare.

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