Early warning system developed for avian influenza

Victorian Primary Industry researchers have developed a real-time polymerase chain reaction (PCR) test that will become the basis of an early-warning system for avian influenza.

Dr Simone Warner, microbiology leader at DPI's Attwood research centre said the new test can identify any avian 'flu strain circulating in commercial poultry flocks or migratory waterbirds in less than 24 hours.

Warner said the current gold standard test, which involves injecting virus into embryonated eggs, takes up to three weeks to deliver a result -- far too late for animal health authorities to implement quarantine measures to contain an avian 'flu outbreaks.

Warner, whose research group developed the test, says it will cover all 15 major haemagglutinin serotypes of influenza circulating in the world's waterbird populations, using primers targeted to a highly conserved structural protein in the virus.

Experiments have confirmed that the PCR test can detect the deadly H5N1 'bird 'flu' currently circulating in south-east Asia, which, unlike most influenza strains, is capable of being transmitted directly from birds to humans.

The virus was recently found to have killed wild geese in Asia, a strong indication migratory birds harbour the strain, providing a potential avenue for the virus' arrival in Australia.

Warner said the plan is to use the test as the basis for a national surveillance system, coordinated by the federal government, in which each state would routinely test swabs taken from sentinel poultry flocks and wild waterbirds found within its borders.

Warner said Victoria had already designed its surveillance program, using internationally recommended protocols.

"We believe that it will soon become mandatory for countries wanting to declare themselves free of avian influenza to implement a testing and surveillance program, rather than claim to be influenza-free simply because they haven't looked closely enough," Warner said.

Dr Catherine Ainsworth, research director for Animal Health Sciences at DPI Attwood, said Victoria has been using the real-time PCR test to sample wild waterbirds since October 2004, and has collected 1500 samples.

DPI officers received help from Department of Environment and Sustainability staff, and amateur ornithological groups like the Victorian Waders Study Group, in collecting samples.

The national surveillance programs will take into account the migratory paths of different bird species, the location of current Asian outbreaks, and areas where local and migratory birds co-mingle.

Ainsworth said the department will soon publish details of the test in the research literature, and will make the test available free to nations that do not currently have avian influenza outbreaks.