More than 20,000 chickens died from an outbreak of H7N9 bird flu in northwest China's Shaanxi Province, the local government said on Wednesday.
The bird flu virus spread within the Yuyang Lyuxiangyuan Eco Co., Ltd., a private poultry company, the government of Yuyang District, Yulin City said in a statement.
Chickens started dying on May 25, it said. A three-kilometer-radius area has been closed for disinfection, and the area will be closed for 21 days starting on Tuesday, the statement said.
All poultry within the area will be culled and all poultry trading sites in the area have been closed, the statement said.
The company is located in Niujialiang Township.
H7N9 is a bird flu strain first reported to have infected humans in China in March 2013. Infections are most likely to strike in winter and spring.
According to the National Health and Family Planning Commission, in March, 96 H7N9 infections and 47 deaths were reported nationwide. In April, 81 infections and 24 deaths were reported.
