An international team of flu experts will go to China this week to help with investigations into the deadly H7N9 virus, the World Health Organisation (WHO) said.

The new strain of avian flu has killed 14 of 63 people known to have been infected, but no human-to-human spread of the virus has been confirmed.

" From what we know at the moment, the poultry markets have been a focus of attention, but the fact-finding mission will be looking into this as a key target of its research," a WHO spokesman told a news briefing yesterday.

The team includes four specialists in areas such as emerging viruses, human-to-animal flu viruses and epidemiology.

He added that the mission wants to investigate how some people seem to fight off the infection. He said: "There are some examples of mild cases, and also some cases of people improving, who have gone from critical to a stable condition, and that is something that will be explored by the fact-finding mission."

China confirmed on Saturday that a seven-year-old child had been infected by the virus in the capital Beijing, the first case outside eastern China's Yangtze river delta region, where the new strain emerged last month.

No date has been set for the arrival of the team, which is expected to hold talks in Beijing and visit affected provinces.

The American, European, Australian and Chinese experts will get under way by Saturday and are expected to carry out a week-long study.

China's poultry sector has lost more than 10 billion yuan (£1bn) since reports emerged of the new bird flu strain two weeks ago.