A child in the south-east part of China has become the 10th person to be killed by bird flu. The girl, aged 9, died on Monday in the Zhejiang province, being the second Chinese citizen to die of bird flu in less than a week. She fell sick on February 10 with fever and pneumonia, after visiting the home of some relatives whose chickens died while she was there, but the cause of her infection still remains to be investigated. People who came in contact with the girl are kept under surveillance and have shown so far no symptoms. Almost all human infections are though to be caused so far by direct contact with birds. A mutation of the virus, making it transmissible among people, can cause a global pandemic, as scientists fear. Since 2003, H5N1 killed 95 people, mostly on the Asian continent. Since February, tens of countries have reported outbreaks of the virus. Despite China's massive inoculation effort, outbreaks are still very frequent. Officials have vaccinated massive flocks of chickens and ducks but infections are still reported. This week, a six-year-old boy was released from the hospital, being cured from the bird flu he contracted in December, after 44 days of isolation.