A seven-year-old girl who contracted the H7N9 strain of bird flu left hospital on Wednesday and appeared before media in an apparent bid by health authorities to cool concerns about the deadly virus.

The daughter of poultry traders was Beijing's first confirmed human case of the virus, which has killed 17 people and infected scores of people hundreds of miles (kilometres) away in eastern China over the past few weeks.

Wearing a bright blue coat and pink backpack, she said she was feeling "much better", at a press conference held by hospital authorities.

"I miss home... I want to return home and play," she said.

She wore a face mask, in what hospital authorities said was a measure to protect her identity.

They said that she recovered after seven days of treatment combining Western and Chinese medicine.

China has confirmed a total of 82 human cases of H7N9 avian influenza since announcing about two weeks ago that it had found the strain in people for the first time.

No vaccine to protect against the virus currently exists.

The girl's mother and father, who had been quarantined for observation, left hospital with their daughter.

Health authorities in China say they do not know exactly how the virus is spreading, but it is believed to be crossing to humans from birds, triggering mass poultry culls in several cities.

Concern has also prompted Chinese consumers to avoid eating chicken, causing huge losses to the country's poultry sector.

The United Nations' Food and Agriculture Organization has said H7N9 shows "affinity" to humans while causing "very mild or no disease" in infected poultry, making finding the source of transmission more difficult.

The World Health Organization has said there is no evidence of human-to-human transmission.