2014-2019年中山市H9亚型禽流感监测及病例特征分析

目的 分析中山市H9亚型禽流感病毒外环境监测情况及人感染H9N2禽流感病例特征,指导H9N2禽流感防控工作。 方法 2014-2019年采集监测镇区内的禽类批发市场、活禽销售市场和生鲜禽销售市场3类交易场所的外环境标本进行禽流感病毒核酸检测,并对人感染H9N2禽流感报告病例进行流行病学分析。 结果 共采集和检测外环境标本9 015份,检出H9亚型禽流感病毒阳性标本2 171份,阳性率为24.08%。阳性率自2015年起呈逐年上升的趋势(趋势χ²=785.258,P<0.001),不同季节均有一定程度流行。监测镇区均有阳性检出,总体阳性率较高的是五桂山、东升、沙溪、东凤、神湾和小榄等镇区。由不具备独立集中屠宰场供货的生鲜禽销售市场的阳性率最高(36.84%,231/627)。鸡与其它禽类混养阳性率增高(28.91%,920/3 182)。采样部位为冰箱等生鲜禽存放器的阳性率最高(32.71%,105/321),其次是笼具(31.27%,491/1 570)。 期间报告3例人感染H9N2禽流感病例,均为常规监测所发现。病例发病时间在冬季或夏季,均有活禽暴露史。 中山市涉禽环境中普遍存在H9亚型禽流感病毒,不同季节均有流行风险。生鲜上市设置独立屠宰区,禽类单独存养,注重冰箱、鸡笼等的消毒清洁,有助于提高防控效果。强化监测有利于及早发现感染病例。

Surveillance and case characteristics of H9 subtype avian influenza in Zhongshan City,2014-2019

The H9 avian influenza virus environmental surveillance and cases of human infection with H9 N2 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 H9 N2 avian influenza.A total of 9015 samples were collected,and the positivity rate of the H9 subtype was 24.08%.The rate had been increasing each year since 2015(trendχ²=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%,920/3182).Refrigerators had the highest positivity rate(32.71%,105/321),followed by cages(31.27%,491/1570).Three cases of human infection with H9 N2 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(H9 N2)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.