As the number of swine flu cases in Australia soars past 4,500, new research indicates that indigenous people may be more susceptible to the contagious virus, compounding an array of existing health conditions.  The findings have been detailed in the medical journal The Lancet. The authors have warned of a looming international public health catastrophe.

Experts are concerned that indigenous peoples, such as Australia's Aborigines and Native American Indians, suffer poor health that puts them at higher risk from the H1N1 virus, which is commonly known as swine flu.

One Aboriginal man in Australia has already died from the infection, while Native Indians in Canada have seen many cases.

Australian researchers, writing in The Lancet, have warned that the risk of indigenous groups contracting the potentially deadly respiratory disease is heightened because they are more likely to be malnourished and living in poverty.

They say the "Westernization" of diets has exacerbated health problems.  Many indigenous people now eat foods loaded with excessive sugar, salt and fat.

The researchers say other factors have also contributed to this increased vulnerability to swine flu, including the widespread use of alcohol, drugs and tobacco.

Professor Michael Gracey, a medical advisor to the Aboriginal-run organization Unity of First People of Australia, says lifestyle diseases have left indigenous populations more susceptible to the H1N1 virus.

"Their general poor standard of health and the fact that many Indigenous people in Australia unfortunately are smokers or have been smokers makes them much more susceptible to respiratory illnesses," he said.

Experts say another problem faced by aboriginal communities is their geographical isolation and lack of medical workers.

Ten people have died in Australia from swine flu, including a three-year-old boy.  In the northern state of Queensland, prison inmates are being given antiviral drugs after outbreaks in two penal institutions.

The authorities say that for most patients, swine flu has caused only a mild illness.

Elsewhere in the South Pacific, almost one thousand cases of the virus have been confirmed in New Zealand, while a handful of infections have also been reported in Vanuatu, Fiji and Papua New Guinea.