Third case of swine flu in Australia

A third swine flu case has been confirmed in Australia, NSW Health Minister John Della Bosca says.

A NSW woman caught the virus while travelling in the United States earlier this month and was prescribed Tamiflu while still overseas, Mr Della Bosca said.

She had recovered from the illness and was no longer considered infectious when she returned to Australia last week, he said.

She is now regarded as NSW's first swine flu sufferer after US authorities on Tuesday confirmed she had contracted the virus, NSW Chief Health Officer Kerry Chant told reporters.

Her travelling companion, another woman, had experienced "a mild respiratory illness which could have represented a mild case of human swine influenza", Dr Chant said.

From 11.30pm (AEST) on Tuesday, NSW authorities began contacting the 13 travellers who were seated near the second woman on the flight back to Sydney.

She said authorities had collected samples from individuals who were on the flight.

"That will be archived and should a test become available in the future, we can retrospectively go back and determine it, but we will never, ever be able to clarify whether that travelling companion had the disease or whether it was something else," Dr Chant said.

Mr Della Bosca revealed the swine flu case soon after Victorian authorities said a nine-year-old Melbourne boy had the illness.

The boy recently returned from a trip to the United States, Victorian Health Minister Daniel Andrews says.

Mr Andrews says the boy is recovering at home and was not ill enough to be hospitalised.

"The child's symptoms appeared on Monday and based on what we know about this form of influenza, agencies do believe he was not infectious when he returned to Australia on May 12," Mr Andrews said.

He said the boy's parents and siblings had all been tested and treated with Tamiflu and were in isolation in their home.

Victoria's Acting Chief Health Officer Dr Rosemary Lester said the test results from the rest of the family were expected during the next few days.

She said other precautions included contacting other passengers on flight QF94 from Los Angeles to Melbourne on May 12 who were sitting close to the family.

"Based on what we know about this form of influenza, passengers on the flight are highly unlikely to become unwell because we strongly believe that the boy was not infectious when he travelled," Dr Lester said.

She said any other passenger of the flight with concerns can call the Swine Influenza Hotline on 180 2007.

It is Victoria's first confirmed case of swine flu.

Australia's first case was a 28-year-old NSW woman who flew into Brisbane from Los Angeles on May 7.

The woman was no longer infectious and had a weak strain of the virus.