Hendra virus in flying-foxes
Flying-foxes are a host of Hendra viruses (HeV), which cause a fatal disease in horses and humans. This includes both the original HeV and the variant strain.
Flying-foxes do not show any apparent signs of illness when infected with HeV.
Original Hendra virus
All 4 species of flying-fox found on mainland Australia have shown evidence of carrying the original HeV.
The virus was first discovered in horses in Brisbane, in 1994. Horses are infected directly from flying-foxes, or via their urine, body fluids, or other excretions.
There is no evidence that exposure to flying-foxes can infect humans with HeV – all human cases have resulted from direct contact with infected horses.
Evidence of infection has also been seen in 2 dogs that were in contact with infected horses.
Hendra virus genotype 2
A variant strain, Hendra virus genotype 2 (HeV-G2), is closely related to the original Hendra virus.
HeV-G2 was detected in small numbers of grey-headed and little red flying-foxes in 2013, from limited samples collected in Victoria, South Australia and Western Australia. Other bat species may potentially carry the variant virus.
In early 2021, HeV-G2 virus was detected in historical samples from a horse in south-east Queensland, which showed severe illness but was found negative to HeV by routine testing.
This virus was also detected in an unvaccinated horse near Newcastle, NSW in October 2021.
Risk of Hendra virus in SA
Although HeV have been detected in flying-foxes in South Australia, they have not yet been detected in horses.
Given the similarity of HeV-G2 to the original HeV strain, the findings show that:
- all areas in Australia where flying-foxes and horses co-exist are at risk of HeV spillover
- there is a similar risk of HeV spread from infected horses to humans.
Avoiding infection
You should assume that all flying-foxes may carry Hendra viruses. Find out the precautions you should take to:
- minimise the risk of Hendra virus infecting horses
- manage human exposure to flying-foxes.