Research Update: Hendra Virus

(Uploaded by Plazi for the Bat Literature Project) Hendra virus was first isolated in 1994 from an outbreak of disease in a racing stable located in the northern Brisbane suburb of Hendra less than 10km from the city centre. The outbreak resulted in death of a horse trainer and 13 horses and left a stable hand seriously ill. A further seven horses with evidence of exposure to the virus were humanely destroyed to avoid possible further spread of the disease. Subsequent incidents from the north of Queensland in Cairns to the New South Wales border at Murwillimbah have led to the deaths of a further three people and 22 horses. Despite these periodic and ongoing incidents, Hendra remains one of the world's rarest diseases. Scientific evidence suggests that Hendra virus is carried by flying foxes. Under unknown but rare circumstances, the virus spills over from these bats to susceptible horses, killing over 70% of the horses it infects. Under even rarer circumstances, the virus spreads to humans who have had very close contact with Hendra infected horses. While there is strong evidence to support this mode of transmission (bat-to-horse-to-human) there is no evidence of bat-tohuman, human-to-human, or human-to-horse transmission of the virus. Since Hendra virus was first isolated, significant progress has been made in understanding the virus, where it originates in nature, and how to detect infection and past exposure. Shortly after the September 1994 outbreak, researchers isolated and characterised the virus, developed laboratory tests to detect infection in both humans and animals, and identified the likely source of the virus. Processes have been put in place to reduce the likelihood of outbreaks based on the knowledge obtained from these studies. While there have been significant gains in knowledge about Hendra, much remains to be learnt. Ongoing studies address the nature of the infection in bats including how and where infection occurs, how Hendra persists in bat populations, and how the virus is transmitted to horses and subsequently to humans. As new technologies are developed, better laboratory tests will be designed to detect and monitor past and current infections. And future research will be directed towards developing better outbreak prevention and control, and potential vaccines and treatments.