The Chinese government announced on Tuesday that a 19-year-old teenager girl from Beijing died of avian flu. This is the first human case of the virus from China since February 2007 and has put the health officials on higher alert for a possible outbreak of the disease due to this winter.

The girl, who lived on the outskirts of Beijing, died on Monday because of the H5N1 strain of bird flu, as a statement released by the Beijing health bureau announced. Yet, the statement didn’t say how the girl got infected with the virus. She supposedly got the virus while she was preparing and slaughtering the poultry, according to a statement released by the World Health Organization.

Mao Qun'an, the spokesman for the Ministry of Health, said that the health officials from China are now considering a future increase in the number of cases of avian flu among birds this year. This virus is thought to be able to infect people too, especially this winter. Mao added that they are paying a lot of attention to the possibility of human infections.

Even if the avian flu represents a big threat for the birds and not for the humans, the World Health Organization and the health authorities stay at high alert because the virus is able to mutate into a more contagious form and start a pandemic. According to the Associated Press, an 8-year-old girl from Vietnam was also diagnosed with the disease on Tuesday.

The people who were in contact with the 19-year-old teenager were also put under close observation, but none of them showed any sign of infection until now, according to the health officials. The disinfection team went to the area where she lived, on Monday.