Of bats, bugs and men: Lessons for Australia in 2008

A biosecurity year in review

The equine ‘flu outbreak was a reminder to all Australians that our health and our livelihood continue to be at risk from emergency disease outbreaks.

Avian flu continued its spread into people in Asia. And England’s foot-and-mouth disease outbreak reminded us of the $10 billion threat foot-and-mouth poses to our livestock and food exports. But fortunately we didn’t see any of the ‘big ones’ here.

So what did happen and what can we learn for 2008? We’ve put together a brief overview of events in 2007. A longer article is also available here with more details on each disease.

Scientists from the Australian Biosecurity Cooperative Research Centre are available for interview.

Equine influenza struck Australia in August. It was largely contained by Christmas thanks to sterling work by NSW and Queensland agriculture departments, but at a direct cost of some $35 million. The impact on the industry was in the hundreds of millions of dollars.

The control program was made a little easier by a new rapid test developed at CSIRO’s Australian Animal Health Laboratory, which was transferred to all state government veterinary laboratories during 2006.

“CSIRO’s test was intended primarily for avian ‘flu,” says Stephen Prowse, CEO of the Australian Biosecurity Centre. “But the state laboratories were also able to use it to test for equine ‘flu getting results in hours rather than days.”

As far as avian influenza itself goes, the big story is no story. The situation has not changed much in the past year, and that’s a worry, according to Prowse. “The longer the problem exists, the higher the risk.”

“Avian influenza appears to be endemic in poultry in Asia,” says Prowse. “Every few weeks there are reports of human infection and fatality in Indonesia.”

A vaccine and vaccination strategy for humans is needed, he says. “But progress is being delayed by arguments over intellectual property ownership of the Indonesian virus samples.”

Aside from the problem of human deaths, avian influenza remains a huge risk to birdlife. Wild birds are being monitored in northern Australia and South-East Asia in the hope of identifying early strains.

Another emerging pathogen, equally virulent, is Nipah virus. It’s spread by fruit bats and flying foxes, and kills up to 75 per cent of its human victims.

It’s related to Hendra virus, discovered in 1994 after the death of a horse trainer and several horses in Queensland. Nipah virus came to light in Malaysia. Now it has appeared in India and Bangladesh where it’s spread from human to human. “Both viruses are harboured and spread by bats,” says Prowse.

A third emerging virus causing concern is chikungunya. This mosquito-borne virus was originally identified in Tanzania in the early 50s. It causes fever and severe joint pain but rarely death.

Since 2005, however, chikungunya virus changed. In 2006 a third of the population on the French island of Réunion in the Indian Ocean was infected — over 250,000 people. Over 200 people died.

Eight cases have been reported in travellers to Australia.

“The Australian Biosecurity Centre is investigating if Australian mosquitoes can also transmit the chikungunya virus and whether we can distinguish it from the endemic Ross River virus,” says Prof John MacKenzie, deputy CEO of the Centre. MacKenzie is organising a national meeting on the threat of chikungunya in mid-February.

In 2007, the UK suffered its second outbreak of foot-and-mouth disease (FMD) in six years. The 2001 outbreak originated from swill feeding at a pig farm in northern England. But the 2007 outbreak was an “own goal”, traced to a sewage leak at England’s major FMD research facility.

While problems in the UK pose little risk to Australia, according to John Edwards, dean of the vet school at Murdoch University in Perth, we need to keep an eye on FMD in South-East Asia.

“Australia has good quarantine arrangements and that’s kept us free for the past 140 years,” he says. “But our biosecurity would be enhanced by eradicating FMD to our north.” FMD has been eradicated in the Philippines and Indonesia with Australian help but has been spreading in Malaysia and Vietnam. The Centre is assisting in the fight by training South-East Asian veterinary scientists.

There have been plenty of other biosecurity battles over the past year. Two areas where measures appear to be working are in aquaculture and the citrus industry.

§ In late 2005, a herpes virus was first detected in four abalone farms in Victoria’s Western District. They’ve been cleaned up and are back in business. But the virus is also in wild populations around the reefs of south-western Victoria and appears to be expanding its range.

§ Citrus trees are now being replanted around Emerald in central Queensland, after a nasty brush with the bacterial disease citrus canker. Up to 500,000 citrus trees were destroyed in the fight against the disease. The Emerald area has been disease-free since the beginning of 2006, and replanting began last July.

But it’s worth remembering that we, the travelling public still pose the greatest threat to our nation’s biosecurity. Last year 4,100 people were fined for serious breaches of quarantine. Ten times that number were cautioned. And twelve tonnes of poultry products alone were confiscated.

We’ve prepared a feature.

For further details on each story information on each story please visit our web or contact Niall Byrne on 03 9398 1416, niall@scienceinpublic.com.au.

Photos

For high-res versions for these photographs please contact Niall.