Hendra virus confirmed in flying foxes in broad region of Australia 

• New Hendra virus (HeV) variant confirmed to have caused death in a horse in New South Wales. 
• “Horses as Sentinels” researchers recently discovered this new Hendra virus variant in historical horse samples. 
• Reminder that Hendra virus disease risk to horses and people who interact with horses, can be reduced through appropriate biosecurity methods including  vaccination and personal protection equipment. 

Scientists at CSIRO, Australia’s national science agency, have confirmed Hendra virus can be found across a broad region of the country, after uncovering a previously unidentified type of Hendra virus in flying foxes in the southern and western states.  

Previous studies had suggested the black and the spectacled flying foxes were the primary carriers of Hendra virus. A new study published in Virology Journal today found the new genetic type of Hendra in grey-headed flying foxes in Victoria and South Australia from 2013 - 2021, and in the little red flying fox in Western Australia in 2015, confirming the virus can be found in all four species of flying foxes and in a broad geographic range of Australia. 

Flying fox research is crucial to our understanding of the viruses they can carry, and the factors leading to transmission. 

“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.” Said Dr Kim Halpin of the CSIRO. 

Spill over of the disease from flying foxes to horses has only been reported in Queensland and New South Wales, however, because the new genetic type of Hendra virus (variant Genotype 2) is so genetically similar to the original Hendra virus, there is a risk to horses wherever flying foxes are found in Australia.  

Just last week on October 5, detection of the new variant in a fatal horse case near Newcastle was confirmed. This is the southernmost case of Hendra virus detection in horses so far recorded and underscores the importance and early public dissemination of information about the retrospective discovery of the variant in a 2015 Queensland horse case and its association with grey-headed flying foxes made by the “Horses as Sentinels” research group in March this year.    

The “Horses as Sentinels” research group and the CSIRO have fine-tuned diagnostic tests so they can detect and differentiate both types of Hendra virus in horses with a high degree of accuracy. You can read more about the work of the ‘Horses as Sentinels’ project which was supported by the DAWE’s Biosecurity Innovation Program here. 

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. While more research is needed, given the similarities to the original strain of Hendra virus, experts suggest we should expect the existing Hendra virus vaccine for horses and the post exposure monoclonal antibody to work against this variant. 

Dr Steve Dennis, President of Equine Veterinarians Australia said the research is a reminder of the risk of Hendra virus.   

“Owners and any people who interact with horses can reduce the risk of infection from Hendra virus by vaccination of horses, wearing appropriate personal protection equipment, removing feed and water from underneath trees frequented by flying foxes, moving horses out of paddocks when trees attractive to flying foxes are flowering, and seeking early veterinary attention for sick horses“ Dr Dennis said.