BEIJING - Over 500 fowl were killed in Beijing's suburban Shunyi District, where the city's first case of H7N9 bird flu was reported on Saturday, a district official announced on Sunday.

The slaughter came after a seven-year-girl in the district was confirmed to have been infected with the new strain of avian influenza.

She developed flu symptoms on Thursday and was sent to Beijing Ditan Hospital for treatment. She is now in stable condition, local officials said at a press briefing.

The girl's parents were engaged in live poultry trading. They have been placed under medical observation and have not shown flu symptoms. The 75 fowl they sold in Shunyi were bought from a businessman from the municipality of Tianjin.

Health authorities have sterilized the girl's home, the school she attends, local bird trading markets and sewage systems in a bid to control the spread of the virus.

Similar bird culling efforts were made earlier this month in Shanghai, where the H7N9 virus was detected in pigeons sold at a local market.

The virus has sickened 57 people in China thus far, of which 11 have died. There is no clear evidence that the virus can be transmitted between humans.