Objective  To explore external environment contamination and human infection risk of avian influenza A (H7N9) virus in Anqing municipality of Anhui province and to provide evidences for developing relevant prevention and control measures.

  Methods  Using random sampling, we collected 324 poultry-related specimens at 38 farmers' markets and 4 houses of patients diagnosed with avian influenza A (H7N9) virus infection in Anqing mucicipality between 5th January and 22nd February, 2017. We detected common nucleic acids of influenza A with real-time fluorescent quantitative (RT-PCR) for all the specimens and avian influenza A (H7N9) specific nucleic acids for all influenza A virus positive specimens.

  Results  The positive rate of H7N9 virus nucleic acid was 28.40% for all the specimens. Positive specimens were detected in 90.90% (10/11) of the sampling regions (county or district) of the municipality. The positive rate of specimens collected in main urban areas was significantly higher than that of specimens collected in other urban areas (χ² = 9.23, P < 0.05). The positive rate of chicken-related specimens was 37.68% and significantly higher than that of duck- and pigeon-related specimens (χ² = 6.57, P < 0.05). The positive rate for specimens sampled at poultry markets was 29.21%, while no positive specimens were detected for the specimens sampled in the houses of H7N9 virus infected patients, with a significant difference (χ² = 6.24, P < 0.05). For the ten types of specimens, the positive rates were the highest (42.86% and 40.00%) for poultry throat and anal swabs, followed by drinking water and sewage samples. Nonsignificant higher positive rate was detected for external environment specimens collected at houses of the H7N9 virus infected patients before the infection incidence compared to those after the infection (χ² = 1.79, P > 0.05).

  Conclusion  Avian influenza A (H7N9) virus contamination existed in poultry markets of Anqing municipality.