广西贵港市首例人感染H5N6禽流感死亡病例的临床特点及流行病学分析

Clinical characteristics and epidemiological analysis of the first human death from H5N6 avian influenza in Guigang,Guangxi

目的分析贵港市首例人感染H5N6禽流感病例临床、流行病学特征,为制定监测方案与防治措施提供科学依据。方法收集病例临床诊疗资料、流行病学资料,并对密切接触者、感染来源采集相关生物和环境标本进行实验室检测,应用描述性流行病学方法进行分析。结果贵港市首例人感染H5N6禽流感病例为单个散发病例,密切接触者无感染,早期临床表现无特异性,临床表现主要为发热、鼻塞、咽喉肿痛,偶有咳嗽,8天后进展为呼吸困难,胸片示右中下肺实变,左胸间隙肺大泡,胸膜炎,白细胞数目先下降后上升,因呼吸和循环衰竭死亡。发病前一周有明确的禽类接触史,密切接触者24名均未出现发热及相关呼吸道症状,采集其中9人份咽拭子H5N6病毒核酸检测均阴性。对患者居住地、患者老家、临近患者居住地养殖有禽类的邻居家和附近的活禽交易市场进行外环境病原学采样检测,共采集了19份,H5、H9病毒核酸检测混合阳性3份,阳性率为15.79%,H9病毒核酸检测阳性7份;扩大城乡活禽交易市场监测范围,采集了10个乡镇农贸市场外环境标本共30份,8个市场检出H5亚型阳性,市场检出率为80%。结论该病例为本地感染病例,感染来源与接触禽类有关,未发现人传人的证据。该病例临床特征不明显,早期症状类似普通感冒,且咽拭子采样检测结果为阴性,对早期诊断造成困难,诊断不及时治疗效果差。市场活禽摊档污染严重,应加强市场卫生管理,加强不明原因肺炎监测工作,在禽流感高发季节应对不明原因肺炎病例多次采样检测,扩大人间和禽间流感病毒监测是早期发现和及时控制人感染高致病性禽流感疫情的关键。

Objective It was aimed to analyze the clinical and epidemiological characteristics of the first case of human infected with H5N6 avian influenza in Guigang, and provide scientific evidence for the development of monitoring programs and prevention measures. Methods The clinical diagnosis and epidemiological data of the case was collected, and the related biological and environmental samples collected from close contacts and infection sources were tested in the laboratory. Descriptive epidemiological method was used for analysis. Results The case of human infection with H5N6 avian influenza in Guigang was a single sporadic case. The close contacts had no infection. The early clinical manifestations were non-specific, mainly including fever, nasal congestion, sore throat, and occasional cough. The case progressed to dyspnea after 8 days, showing a consolidation in right middle and lower lung and a left chest interstitial lung vesicles as well as a pleurisy in chest radiograph with white blood cell count decreased first and then rise, died of respiratory and circulatory failure. There was a clear history of poultry exposure in the week before the onset of illness, and 24 close contacts did not have any fever and related respiratory symptoms. Nine of the throat swabs were negative for H5N6 virus. Pathogen test was carried out on the external environmental samples from living place of the patient, the patient's home, neighboring house where the poultry was bred, and the nearby live poultry trading market. A total of 19 samples were collected, of which 3 samples had both H5 and H9 virus nucleic acid, with a positive rate of 15.79%;and 7 samples had H9 virus nucleic acid;the monitoring of live poultry markets were expanded in urban and rural areas, a total of 30 environmental samples were collected from 10 rural farmers markets, and 8 markets were positive for H5 subtype, with a detected rate of 80%. Conclusion This case is a local infection. The source of infection is related to exposure to poultry. No evidence of human transmission has been found. The clinical features of this case are not obvious, with early symptoms are similar to the common cold and negative pathogen test results for throat swab samples, which makes the early diagnosis more difficult and not timely. The live poultry stalls in the market are seriously polluted. Market health management and surveillance of unexplained pneumonia should be strengthened, and multiple cases of unexplained pneumonia should be tested in the high season of avian influenza. Expanding human and avian influenza virus surveillance is the key for early detection and timely control of human infection with highly pathogenic avian influenza.