Abstract:The H9 avian influenza virus environmental surveillance and cases of human infection with H9N2 virus in Zhongshan City from 2014 to 2019 were analyzed in this study. In 2014-2019, environmental samples from wholesale, live poultry and fresh poultry markets in the monitored towns were collected, and nucleic acids of avian influenza virus were detected. Epidemiological analysis was conducted on the reported cases of human infection with H9N2 avian influenza. A total of 9 015 samples were collected, and the positivity rate of the H9 subtype was 24.08%. The rate had been increasing each year since 2015 (trend χ2=785.258, P<0.001), and the prevalence differed by season. All monitored towns had positive detection, and the overall positivity rates were relatively high in Wuguishan, Dongsheng, Shaxi, Dongfeng, Shenwan and Xiaolan. The highest positivity rate was found in fresh poultry markets that did not have independent slaughterhouses (36.84%, 231/627). The presence of chickens with other birds increased the positivity rate (28.91%, 920/3 182). Refrigerators had the highest positivity rate (32.71%, 105/321), followed by cages (31.27%, 491/1 570). Three cases of human infection with H9N2 avian influenza virus were reported, all of which were identified through routine monitoring. All cases involved exposure to live poultry in the winter or summer. The results showed that avian influenza a (H9N2) virus exists in poultry environments in Zhongshan City and poses epidemic risks in different seasons. Setting up independent slaughterhouses for fresh products, keeping birds separately, and emphasizing the disinfection and cleaning of refrigerators and cages would help to improve virus control. Strengthened surveillance would aid in identifying cases of infection.
陈楚莹, 王曼, 冯志锋. 2014-2019年中山市H9亚型禽流感监测及病例特征分析[J]. 中国人兽共患病学报, 2021, 37(2): 122-127.
CHEN Chu-ying, WANG Man, FENG Zhi-feng. Surveillance and case characteristics of H9 subtype avian influenza in Zhongshan City, 2014-2019. Chinese Journal of Zoonoses, 2021, 37(2): 122-127.