With a case of young woman in WA infected with the pandemic virus, Australia has recorded its first major case of swine flu infection for the year.

Earlier this month, the woman was admitted to a Perth hospital, when the surveillance program set up to watch for the spread of the A (H1N1) was notified of her deteriorating condition. She is also places in a higher-risk group for a serious swine flu infection due to her existing illness, said Associate Professor Paul Kelly.

This is our first off the rank (for 2010), said Dr Kelly, of the National Centre of Epidemiology and Population Health at Australian National University.

It's the first sever enough to lead to hospitalization in the group of hospitals that we monitor.

As far as I know she is fine.

Across the country, thirteen major hospitals are participating in the Influenza Complications Alert Network, or FluCAN, set up to tract the virus' spread at the severe end, said Dr Kelly.

He said the early case was a reminder that the swine flu which started last year's global pandemic would return to a wide circulation in Australia, this winter, and possibly again in 2011.

He reminded Australians who have yet to get immunized, to do so by getting the free vaccines offered by GPs through the federal government's initiative.

We also need to be alert to the fact that each week tens of thousands or people come into our country from the northern hemisphere which has just gone through its latest influenza season, said Dr Kelly.

The pandemic which started in Mexico early last year, have swiftly spread globally, with a total of 37,000 cases in Australia. About 5, 000 Australians were hospitalized with the infection, 700 admitted to intensive care units, and 191 died.