Surveillance in 2013 of avian influenza virus from live-bird markets in Bangkok, Thailand

Live-bird markets have been implicated in transmission of avian influenza viruses, most recently of influenza A (H7N9) in China. Low pathogenic avian influenza (LPAI) viruses, such as H7N9, cause asymptomatic infections in poultry, and active surveillance is required to detect infection and to prevent transmission to humans. Although limited numbers of live birds for consumption are sold in Bangkok live bird markets (LBM), transmission of H7N9 in nearby China has prompted a program of active surveillance for avian influenza in Bangkok LBM to determine LPAI viruses. In November 2013, Bangkok One Health team organized avian influenza surveillance in all nine districts of Bangkok with LBMs. Oropha-ryngeal swabs (n = 834), sera (n = 375) and fresh feces (n = 420) were taken from 400 chickens, 20 ducks, 20 geese and 394 pet birds from 75/87 shops. Additionally, drinking water (n = 208) and waste water (n = 26) were collected. Samples were tested for influenza A viruses using RT-PCR. In addition, samples were inoculated in eggs and tested by hemagglutination (HA) and hemagglutination inhibition (HI) assays using H5N1- and H7N9-specific antigens. Sera were tested by HI assay using similar antigens. No sample was found positive for influenza A virus. These data provide evidence that avian influenza viruses, including LPAI viruses such as H7N9, were not circulating in Bangkok LBMs during the period surveyed.