A new study conducted by scientists at the CSIRO have uncovered a new type of Hendra virus in flying foxes, confirming the virus can be found across a broader region of Australia than previously thought.
The study was published just days after the new genetic type, known as HeV-g2, was detected in an unvaccinated horse in West Wallsend near Newcastle, the most southerly case of Hendra virus on record.
Previous studies suggested the black and spectacled flying foxes were the primary carriers of Hendra virus, however the identification of a Hendra variant in grey-headed flying foxes in Victoria and South Australia, and in the little red flying fox in WA, confirmed the virus can be across a much broader geographic range in Australia.
The Hendra virus is carried by flying foxes and can be transmitted to horses through droppings and other close contact.
The virus can then be transmitted from horses to humans.
After monitoring flying fox samples from 2013 to 2021, researchers at CSIRO's Australian Centre for Disease Preparedness (ACDP) found the new genetic type in flying foxes in Victoria, South Australia, and Western Australia.
CSIRO scientist Dr Kim Halpin said spillover of the disease from flying foxes to horses has still only been reported in Queensland and New South Wales.
"However, because Hendra Virus Genotype 2 is so genetically similar to the original Hendra virus, there is a potential risk to horses wherever flying foxes are found in Australia," Dr Halpin said.
"It's important to note that Hendra has never been reported to spread directly from flying foxes to humans, it's always been transmitted from infected horses to humans. We expect this new genetic type would behave the same way.
Dr Halpin said the similarities between the two variants of Hendra virus meant scientists expected the current vaccine available for horses should work against the new variant, although more research is needed.
""This finding really underscores the importance of research into flying foxes. It's crucial to helping us understand and protect Australians against the viruses they can carry," Dr Halping said.
A separate project led by the University of Sydney and the CSIRO detected the same genetic variant of Hendra virus earlier this year in samples collected from a horse in Queensland in 2015.
Dr Steve Dennis, President of Equine Veterinarians Australia, said the findings are a reminder there's a risk of Hendra virus wherever there are flying foxes and horses.
"Owners and any people who interact with horses can reduce the risk of infection from Hendra virus and other zoonotic viruses through vaccination of horses or humans where available, wearing appropriate PPE, and seeking veterinary attention for sick horses," Dr Dennis said.
The CSIRO said flying foxes should only be handled by people who are appropriately vaccinated, trained, and wearing personal protective equipment. Injured or sick flying foxes should be reported to a wildlife care organisation or local veterinarian.
While flying foxes can pose a risk to horse and human health, they remain a protected species on Australia's nationally vulnerable list.
The CSIRO said flying foxes are critical to pollinating native trees and without them, there would be no eucalypt forests, rainforests and melaleucas.
Biosecurity measures will help to minimise the risk of disease transmission, while protecting these important species and their role in maintaining a healthy environment, the CSIRO said.