CANBERRA, Australia- Australian experts on Thursday said they have been "blown away" by the case of a man cured of HIV, yet they caution his treatment was too risky to be offered broadly to the world's HIV-infected population.

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A US man in 2007 received a bone marrow transplant to treat a lethal blood disorder, acute myeloid leukaemia, and the transplant was also seen to clear him of the HIV virus.

According to the German-based research as outlined this week in the scientific journal Blood, the US man's donor was known to carry a rare genetic mutation which confers natural resistance to HIV.

Australian scientist said while a world-first in terms of a case of HIV cured, the transplant process was high-risk and around 30 percent of patients do not survive the procedure.

"It's a very high-level and extremely expensive intervention which could only be recommended to people with HIV who have leukaemia," Professor of Sexual Health Basil Donovan, from the University of New South Wales of Australia, was quoted by the Australia Associated Press (AAP) as saying on Thursday.

"There is no guarantee that it would work in everyone that you did it in, but the fact that it worked at all is extraordinary."

Prof Donovan said the transplant involves killing off a patient 's unhealthy bone marrow and white blood cells, leaving them without an immune system before doctors introduce the donated stem cells to reconstitute the bone marrow which now produces healthy cells.

In this case, the new cells were resistant to HIV, and the process also apparently wiped out every last "sanctuary" for the virus within the man's body.

However, AAP reported that just one percent of the European population is known to carry the mutated gene, known as Delta 32, that confers resistance to a HIV infection.

Another 1,050 Australians were newly diagnosed HIV during 2009, the highest number in almost two decades.

It was the fourth year in a row the nation's HIV diagnoses hovered around the thousand mark, up significantly from about 700 cases a year during the late 1990s.

There were 20,171 Australians living with a diagnosed HIV infection at the end of 2009.

Globally, 33.3 million people are living with HIV, and more than 7,000 people are newly infected every day.