New Strain of Hendra Virus in Horses Detected Twice in 2021

The mainstream media might be buzzing with news of the new Omicron strain of COVID-19, but a new strain of Hendra Virus has been detected in two horses this year thanks to newly available technology.  

The strain has been found in both Queensland and New South Wales: 

In March 2021 a retrospective detection was made in a 2015 sample from a horse in Queensland that died unexpectedly. The case was originally reported as a negative Hendra result but has now been identified as the new variant HeV-g2. 

Then in October 2021, the new strain was detected in an unvaccinated horse who was euthanased in West Wallsend – near Newcastle – New South Wales, making it the most southern case of Hendra recorded to date.  

The strain shares similar characteristics to the original Hendra virus but isn’t as easily detected with traditional Hendra testing. New tests will be able to detect the new strain and will be applied to retrospective samples, testing a common hypothesis among scientists who suspect more horses may have been infected in the past without being detected.  

Hendra virus can be transmitted from flying foxes to horses and then from horses to humans. In each phase, the virus is transmitted through high exposure to bodily fluids of the infected animal.  

Previous research concluded that black and spectacled flying foxes were the primary carriers of the Hendra virus, however the new variant has been identified in the grey-headed flying foxes (found in Victoria and South Australia) and little red flying foxes (found in Western Australia). The virus is now known to circulate in four species of flying fox that cover a broad geographical range of Australia.  

Among horses, the symptoms include rapid onset illness, fever, increased heart rate, rapid deterioration with respiratory and/or nervous system signs, and unexpected death.  

With the virus both more widespread than previously thought, and mutating to present as a new strain, it’s more important than ever to ensure horses and humans alike are protected.  

Protect your horses: 

• Protect/cover horse feed and water from contamination (avoid placing under trees or in areas known to contain flying foxes)  
• Vaccinate horses for Hendra to reduce risk of disease (identified as the best protection available for all Hendra strains) 
• Isolate sick horses from others 
• Contact a veterinarian or the Emergency Animal Disease Watch Hotline (1800 675 888) in case of unusual symptoms or unexpected deaths in horses 

Prevent human infection:  

• Practice good hygiene when around horses i.e. don’t kiss a horse’s muzzle, wash hands with soap and water after handling a horse’s mouth or nose  
• Cover any open woods when handling horses 

These biosecurity measure will help minimise the risk of Hendra transmission between horses and humans, simultaneously reducing the risk of flying foxes, which are a threatened, vital species for the Australian ecosystem, being targeted by humans in response.