Feature: Biosecurity and animal-borne viruses

Just down the highway from Lorne on Victoria’s coast is CSIRO Livestock Industries’ Australian Animal Health Laboratory (AAHL) in Geelong. And within the high-level facilities of the AAHL is the world’s largest collection of pathogenic bat viruses.

Some of these – Hendra, Nipah and the SARS-like coronavirus – are very nasty indeed, and no doubt familiar to many due to their infamous associations with severe disease or death in humans and livestock over the last couple of decades.

At the newest meeting on the Lorne calendar, Infection and Immunity, CSIRO’s Dr Lin-Fa Wang talked about his internationally renowned research on such bat viruses and his own evolution from molecular virologist to bat biology specialist.

Bats are known reservoir hosts for an increasing number of zoonotic viruses (animal viruses capable of also infecting people). Interestingly, by some unknown immunological or genetic twist of evolution, the bats themselves seem unaffected by the viral presence.

“We have challenged these animals with a range of samples from our extensive suite of deadly viruses and none even raise a temperature in the bats,” says Wang. Coupled with their mobility and ubiquitous presence, this makes bats the ideal natural reservoir for viruses and, increasingly, a critical target for medical and veterinary research.

Wang’s background is in animal virology, and his interest in bat viruses that can jump species began around 15 years with the 1994 outbreak of Hendra virus (HeV) at a horseracing stable in Brisbane’s northern suburbs.

In collaboration with Queensland Government scientists, and particularly veterinary epidemiologist Dr Hume Field, Wang was pivotal in the rapid characterisation of the virus and for naming it.

Originally named Equine Morbillivirus, Wang’s initial genome work showed that this was not strictly true, and so it was renamed after the site of the first reported case and placed in a genus of its own (Hepanavirus).

HeV has, to date, caused the death of at least 40 horses and four humans (with a 50 per cent mortality rate) in 13 separate outbreaks.

Wang has since been involved in identifying bat hosts for several human infection outbreaks including the Nipah virus in 1998 (closely related to Hendra) and the Melaka virus in 2006, both in Malaysia.

In 2003, an extensive and significant human outbreak of Severe Acute Respiratory Syndrome (SARS) coronavirus led to an international team being formed under the leadership of Wang – two groups from Australia (Wang and Field working together again), two from China and one from the United States.

“We eventually identif ied bats as harbouring what we called SARS-like virus, which is very closely related to the human virus that caused the 2003 outbreak, and published the results in Science in October 2005.

Soon after, a French and South African group identified an African species of fruit bat as a reservoir for the deadly Ebola virus, which they published in Nature in December 2005. It was a big year for bat virology!”

Read part II: Battling Hendra virus

Read part III: Biosecurity batman