Avian influenza virus in live poultry markets in Jinan city, 2015-2016

Abstract

Objective To study the distribution and contamination characters of avian influenza virus in environmental samples from live poultry markets in Jinan city. Methods The environmental samples from live poultry markets across Huaiyin district and Licheng district were collected from November 2015 to October 2016 in Jinan city. Surface swabs of chopping board and cages, feces, poultry sewage as well as drinking water samples were tested by real-time RT-PCR using influenza A specific primers and all the positive samples were further tested with H5、H7 and H9 subtype specific primers. The chi-squared test was used to compare virus prevalence among different sample types and poultry market types. Results Among 2 943 live poultry related environmental samples collected, 13.73% (404) samples were positive for type A avian influenza nucleic acid and 4.32% (133), 0.07% (2) and 8.49% (250) samples were positive for H5, H7 and H9 subtypes, respectively. The subtypes identified were mainly H5 and H9, and the number of samples with H9 subtype were almost two time of H5. The samples with highest positive rate were surface swabs of chopping boards (21.88%,x2=38.535, P<0.001). This finding showed that the positive rate of flu A nucleic acid in environmental samples had seasonality. It was significantly higher in winter and spring with the highest in December, and was lower from May to September. Conclusions Live poultry markets were contaminated most seriously by avian influenza subtypes H5 and H7. The drinking water for the poultry in the wholesale poultry markets and chopping boards in the retail live poultry markets were main infectious sources and should be managed and controlled. Key words: Avian influenza; Virus; Live poultry market; Surveillance