Hendra Virus Fact Sheet


* Hendra Virus (HeV) remains one of the World's rarest diseases

* It was first discovered in 1994 - since then there have been 14 outbreaks, with seven confirmed human infections including four fatalities

* Scientific evidence suggests HeV is carried by flying foxes.

* Susceptible colonies roost right across mainland Australia, not just in Queensland

* Transmission of the virus to horses is thought to be through the ingestion of grass or partially eaten fruit contaminated with bat urine, saliva or other bodily fluids.


* Horses develop an acute onset of clinical signs including increased body temperature and heart rate, a respiratory or neurological syndrome quickly leading to death in most cases.

* The incubation period in horses is 5-16 days.

* Fatally infected horses died on average two days after the first sign of infection.

* Transmission from horses to humans is rare.

* All human infections have occurred following direct exposure to tissues and secretions from infected or dead horses.

* The greatest risk of human infection appears to be through the direct physical contact with the body fluids of ill, dying or dead horses.

* Evidence suggests horses have potential to excrete the virus several days before showing signs of infection.

* Test results show natural transmission is likely to require close contact with an infected animal or exposure to contaminated material shortly after excretion.

* Studies show the virus does not survive for extended periods after excretion from infected animals.

* The incubation period in humans has been estimated at 5-14days.

* There is no evidence of human to human transmission.


* The likelihood of HeV infection in a clinically normal animal is extremely low.

* There has been no HeV health testing requirement made by the Government (Biosecurity Queensland, Department of Agriculture, Fisheries and Forestry etc) for horses moving between jurisdictions or properties.

* Various test results can take between two days to two weeks to be returned.

* For a disease with such low prevalence, the probability of detecting infection by testing healthy horses is extremely low.

*HeV health testing of Queensland horses prior to movement is not scientifically justified, as the tests available are most relevant when a horse is already showing clinical signs consistent with HeV infection.

* It is considered that HeV health testing is a scientifically unsound and unnecessary practice that has the potential to adversely affect the Queensland horse industry.


* Further investigation of both the dynamics of HeV infection in flying foxes and the mode of transmission to horses is clearly required to determine which factors play a role in flying fox infection and the timing and location of virus spill over from flying foxes-to-horses.

* Flying foxes infected with HeV show no clinical signs and appear to be unaffected by the virus.

* HeV antibodies have been found in flying fox colonies in all mainland states of Australia, it is yet to be determined why only outbreaks in Queensland and New South Wales have been detected or reported.

Compiled by the TBQA

Information sourced from Biosecurity Queensland