The risk of avian influenza in birds in Australia.

Avian influenza viruses may cause mild or severe disease in birds. There have been five recorded outbreaks of highly pathogenic avian influenza in birds in Australia, all of which were caused by the H7 subtype. These were quickly controlled and similar coordinated responses are expected for possible future outbreaks of avian influenza. Migratory birds are not regarded as the source of these outbreaks, and the prevalence of avian influenza viruses in wild birds in Australia is very low. Avian influenza H5N1, which emerged in birds in China in 1996, has spread to bird flocks in Asia, Europe and Africa. The main carriers of avian influenza, ducks, do not migrate to Australia, and currently the risk of H5N1 occurring in Australian birds appears to be low. Nevertheless, surveillance and response plans for outbreaks of highly pathogenic avian influenza have recently been upgraded across Australia.