Environmental Sampling for Avian Influenza A(H7N9) in Live-Poultry Markets in Guangdong, China.
BACKGROUND
To provide an increased understanding of avian influenza A(H7N9) activity in live-poultry market in space and time and hence improve H7N9 epidemic control, an ongoing environmental sampling program in multiple live-poultry markets across Guangdong, China was conducted during March 2013-June 2014.


METHODS
A total of 625 live-poultry markets throughout 21 prefecture areas took part in the study. A total of 10 environmental sites in markets for sampling were identified to represent 4 different poultry-related activity areas. At least 10 environmental samples were collected from each market every month. The real time RT-PCR was performed to detect the avian influenza A(H7N9) virus. Field survey was conducted to investigate the sanitation status of live-poultry markets.


RESULTS
There were 109 human infections with H7N9 avian influenza in Guangdong, of which 37 (34%) died. A total of 18741 environmental swabs were collected and subjected to real-time RT-PCR test, of which 905(4.83%) were found positive for H7N9 virus. There were 201 (32.16%) markets affected by H7N9 in 16 prefecture areas. The detection of H7N9 virus in markets spiked in winter months. 63.33% markets (38/60) had no physical segregation for poultry holding, slaughter or sale zones. Closing live-poultry market significantly decreased the H7N9 detection rate from 14.83% (112/755) to 1.67% (5/300).


CONCLUSIONS
This study indicates the importance of live-poultry market surveillance based on environmental sampling for H7N9 Avian Influenza control. Improving live-poultry market management and sanitation and changing consumer practices are critical to reduce the risk of H7N9 infection.
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Min
M
Kang
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Jianfeng
J
He
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Tie
T
Song
Centre for Environment and Population Health, School of Environment, Griffith University, Brisbane, Australia.
Shannon
S
Rutherford
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Jie
J
Wu
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Jinyan
J
Lin
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Guofeng
G
Huang
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Xiaohua
X
Tan
Center for Disease Control and Prevention of Guangdong Province, Guangzhou, People's Republic of China.
Haojie
H
Zhong
D000818:Animals; D002681:China / Q000453:epidemiology; D004783:Environmental Microbiology; D005843:Geography; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype / Q000502:physiology*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology*; D007251:Influenza, Human / Q000453:epidemiology; D011200:Poultry / Q000821:virology*; D060888:Real-Time Polymerase Chain Reaction