Photo taken on April 13, 2013 shows a screen showing a seven-year-old girl, who was infected with the H7N9 strain of bird flu, receiving medical treatment in the Beijing Ditan Hospital, during a press conference held by the hospital in Beijing, capital of China. This was the first such case in the Chinese capital. The child is in stable condition. Two people who have had close contact with the child have not shown any flu symptoms, and the girl's parents were engaged in live poultry trading in a township of Shunyi District in Beijing's northeastern suburbs. (Xinhua/Zhang Yu)

Cheng Jun, a spokesman with the Beijing Ditan Hospital, introduces the situation of a seven-year-old girl, who was infected with the H7N9 strain of bird flu, beside a screen showing the girl receiving medical treatment in the hospital in Beijing, capital of China, April 13, 2013. This was the first such case in the Chinese capital. The child is in stable condition. Two people who have had close contact with the child have not shown any flu symptoms, and the girl's parents were engaged in live poultry trading in a township of Shunyi District in Beijing's northeastern suburbs. (Xinhua/Zhang Yu)

Cheng Jun, a spokesman with the Beijing Ditan Hospital, introduces the situation of a seven-year-old girl, who was infected with the H7N9 strain of bird flu, during a press conference in Beijing, capital of China, April 13, 2013. This was the first such case in the Chinese capital. The child is in stable condition. Two people who have had close contact with the child have not shown any flu symptoms, and the girl's parents were engaged in live poultry trading in a township of Shunyi District in Beijing's northeastern suburbs. (Xinhua/Zhang Yu)

A notice on preventing the H7N9 infections is seen at the fever clinic in the Beijing Ditan Hospital, where a seven-year-old girl in Beijing infected with the H7N9 strain of bird flu is being treated, in Beijing, capital of China. This was the first such case in the Chinese capital. The child is in stable condition. Two people who have had close contact with the child have not shown any flu symptoms, and the girl's parents were engaged in live poultry trading in a township of Shunyi District in Beijing's northeastern suburbs. (Xinhua/Zhang Yu)

Photo taken on April 13, 2013 shows the Beijing Ditan Hospital, where a seven-year-old girl in Beijing infected with the H7N9 strain of bird flu is being treated, in Beijing, capital of China. This was the first such case in the Chinese capital. The child is in stable condition. Two people who have had close contact with the child have not shown any flu symptoms, and the girl's parents were engaged in live poultry trading in a township of Shunyi District in Beijing's northeastern suburbs. (Xinhua/Zhang Yu)