Scientists have identified a new virus in Australian fruit bats. The Cedar virus – named after the suburb in the Gold Coast hinterland where it was first discovered – is part of the henipavirus family, but unlike other members Hendra and Nipah, it does not cause death or disease in the small animals tested so far.
The team, from CSIRO’s Australian Animal Health Laboratory and the Queensland Centre for Emerging Infectious Diseases, hope the discovery will help them understand how Hendra and Nipah cause illness, allowing for the development of antiviral medicines and vaccines.
The findings are published today in the journal PLoS Pathogens.
Henipaviruses were first discovered in the 1994, following a series of outbreak in horses, pigs and humans in Australia and Malaysia.
“Over 70% of people and animals infected with Hendra and Nipah viruses die,” said study co-author Gary Crameri from the CSIRO’s Australian Animal Health Laboratory.
“This ranks henipaviruses amongst the deadliest viruses in existence, yet little is known about just how such viruses actually cause disease or death.
"The significance of discovering a new henipavirus that doesn’t cause disease is that it may help us narrow down what it is about the genetic makeup of viruses like Hendra and Nipah that does cause disease and death,” Mr Crameri said.
The researchers analysed bat urine samples from across Australia and found a high level of antibodies in the the four species of flying fox, showing bats were the natural host of the disease.
They then carried out animal studies on mice, guinea pigs and ferrets – the animals used to detect the impact of henipaviruses on humans – and found it did not make the animals ill.
The virus has not been detected in domestic animals or livestock but Mr Crameri said it was “still too early to rule out cedar virus as a potential to cause illness in other animals”.
Professor Ross Barnard, the University of Queensland’s Biotechnology Program Director, said it was not surprising the researchers had found another bat-borne virus.
“Bats had long been known to harbour a large number of viruses,” he said. “What’s interesting about this study is they seem to have identified one which is similar to Hendra and Nipah but is missing a key gene product that seems to be involved in regulating the immune response.
"The nasty viruses like Hendra and Nipah seem to be able to switch off some of the elements of the immune response, so it means they can do more damage.”
Professor Barnard said the insight would lead to other studies where researchers could swap some of the genes between the viruses to identity which elements influenced the immune response in the infected person and determined whether they became severely ill.