浙江省6例人感染H7N9禽流感确诊病例的临床与流行病学特征分析

Clinical and epidemiological characteristics of the 6 confirmed human cases with novel influenza A （H7N9） virus infection in Zhejiang

目的分析2013年4月浙江省人感染H7N9禽流感确诊病例的临床与流行病学特征，探讨其临床特征、感染重点地区和人群及危险因素。方法采用实时荧光定量PCR检测病例和密切接触者咽拭子H7N9禽流感病毒核酸；采用流行病学个案调查与描述性流行病学相结合方法，收集与分析6例确诊病例的临床与流行病学相关资料；采用SPSS17．0软件进行统计分析。结果6例人感染H7N9禽流感确诊病例主要分布在杭州和湖州地区，平均年龄60．83（M=64．50）岁，男性多于女性（5：1）；咳嗽常为首发症状，主要临床表现有发热、头晕、肌肉酸痛、咳嗽、咳痰以及气促、呼吸困难等，胸部影像学均显示严重肺炎，大部分病例（5／6）有慢性基础性疾病。所有病例均无病（死）禽暴露史，但有高频度农贸市场暴露史，其暴露的农贸市场外环境标本H7N9禽流感病毒核酸阳性率达43.21％。6例病例的375名密切接触者中有32人（8．53％）出现异常症状，但咽拭子H7N9禽流感病毒核酸检测均为阴性。结论人感染H7N9禽流感以急性呼吸系统损害为主要临床表现；老年男性，特别是有慢性基础性疾病者是浙江省人感染H7N9禽流感病例的危险人群，其感染来源可能与禽类暴露有关，暂无充分证据支持病毒的人际传播。

Objective To explore the clinical spectrum, geographic location of human H7N9 avian influenza as well as the characteristics of population at high risk of infection, in order to develop strategies for the prevention and control of the infection. Clinical and epidemiological characteristics on the 6 confirmed human cases in Zhejiang werfe also analyzed. Methods Real-time fluorescent quantitative PCR was used to test the nucleic acid of human H7N9 avian influenza infection, from pharyngeal swabs of the patients and their close contacts. Face to face interview and descriptive method were used to collect related clinical and epidemiological data. Statistical analysis was performed by SPSS 17.0. Results Six confirmed cases were distributed in Hangzhou and Huzhou cities. The 6 confirmed human cases, including 5 males and 1 female were all confirmd with novel influenza A （H7N9） virus infection, with an average age as 60.83 years （with median as 64.50 years）. Cough was the most common initial symptom to be noticed. The clinical manifestations would include fever, dizziness, pain of muscles, coughing, expectoration and short of breath. All the X-ray chest films showed severe pneumonia, and 5 of them having had other chronic diseases. None of the cases admitted to have had a history of exposure to ill/death avians. However, all of the cases had been frequently exposed to the agricultural-byproduct-trading-markets where the positive rate of novel influenza A （H7N9） virus in environmental specimens was up to 43.21%. 32 of the 375 close contacts （8.53%） to the 6 cases appeared abnormal symptoms, but no positive result related to novel influenza A （H7N9） virus nucleic acid was detected from their throat swabs. Conclusion Acute infection on the respiratory system seemed the main clinical manifestation. Elderly men, especially those with chronic diseases were under high risk of human infection with H7N9 avian influenza. The source of infection might be associated with the exposure to poultry. There was still lack of evidence to confirm the route of person to person transmission on H7N9 avian influenza.