For the first time, researchers have found evidence of human-to-human transmission of the new H7N9 bird flu virus, which has killed at least 43 people in China.

According to a report in the British Medical Journal, a 32-year-old woman became sick with the virus in March after visiting her 60-year-old father in the hospital. Prior to visiting her father in the hospital, the woman had had no contract with any birds or poultry. Her father fell ill one week after he visited a poultry farm. Samples taken from both showed a nearly identical strain of virus, supporting the theory that the virus was passed from the father to his daughter.

Both died from multiple organ failure in the intensive care unit.

But don't go panicking quite yet; the researchers said there was no evidence to show that the virus spreads easily or efficiently between people, though they also said the following, so, uh, maybe panic a little.

"Our findings reinforce that the novel virus possesses the potential for pandemic spread," [the study's researchers] concluded.

Other experts noted that human-to-human transmission occurred in other, older strains of the bird flu, none of which reached pandemic levels.

Dr Peter Horby, senior clinical research fellow at the Oxford University Clinical Research Unit in Hanoi, Vietnam, said of the study: 'The most likely source of infection for the daughter was her father, during the period that she cared from him whilst he was ill.'

He said limited person to person transmission had been reported for other strains, H5N1 and H7N7, and the swine origin flu virus H3N2v.

He said the strains have been around for more than a decade, but 'have not progressed any further down the path towards a pandemic virus'.

[Image via AP]

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