No elevated risk to humans from Hendra outbreak: expert

While the news that the Hendra virus has been found in a dog is a new development that warrants scientific attention, there’s no evidence that people are at any greater risk from the virus, says Dr Linfa Wang.

Wang, who just arrived back from Queensland to CSIRO Livestock Industries’ Australian Animal Health Laboratory, is a leading expert on Hendra virus and has been involved in the response to the recent outbreak.

Hendra is an interestingly unique virus, says Wang, because it’s able to infect a wide range of cell lines in the lab and many different animals in the wild. However, it doesn’t appear to be highly infectious.

“Hendra is an interesting virus because, under natural conditions, it’s very hard to transmit,” Wang told ALS. I was speaking to Premier Anna Bligh in Queensland and saying: ‘if you want a silver lining, that’s it’.”

According to Wang the fact that Hendra has been found in a dog is not necessarily unexpected, even if it’s the first time it’s been seen in Australia.

Hendra is related to another virus, Nipah, which was first found in Malaysia. “Nipah has seen bat-to-pig then pig-to-human transmission. Two dogs have died in Malaysia from Nipah, but many more were infected and didn’t die. And in Australia we’ve seen limited host-to-host transmission,” said Wang.

Hendra is also interesting because it affects different species in different ways. For example, it’s relatively harmless in flying foxes but it can be lethal in horses and humans.

Yet Wang stresses that Hendra is still a very rare virus, and transmission from animal to human is equally rare. As such, even with the recent outbreak, there’s not necessarily an elevated risk to people at this stage.

“Currently there is no elevated risk, only elevated interest and alertness,” said Wang. “As a virologist, the number one worry with these outbreaks was whether the virus has changed, but so far the data says it hasn’t changed.”

Wang welcomed the news that the Queensland and New South Wales governments have committed another $6 million to researching Hendra, although he stressed that there are aspects of the research that cannot necessarily be expedited.

“Any funding is welcome,” he said. “However, some of the limiting factors won’t be resolved by funding. There are disease process that we can’t recreate in the lab. The epidemiological and risk factors must be done in the field.”