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目的分析惠州市首例人感染H7N9禽流感病例病原学特征,了解人感染H7N9禽流感的流行规律,为制定防控措施提供依据。方法提取患者标本病毒核酸,利用荧光定量PCR进行检测,扩增HA和NA基因片段并进行序列分析。通过流感强化监测扩大人感染H7N9禽流感病例的主动筛选,采集活禽交易市场、禽类养殖场以及密切接触者标本开展病原学主动监测。结果该患者呼吸道标本甲型流感、H7亚型和N9亚型均为阳性,对血凝素和神经氨酸酶基因序列进行比对和进化分析,显示该H7N9禽流感病毒HA基因与NA基因与已公布的人感染H7N9禽流感病毒序列高度同源。96名密切接触者均未发现感染H7N9禽流感病毒。通过流感强化监测,严重急性呼吸道感染病例274例,发现4例人感染H7N9禽流感病例。活禽交易市场外环境和禽类标本检出3份H7N9禽流感病毒核酸阳性。结论惠州首例H7N9禽流感病例病毒HA及NA特征基因序列与国内流行的病毒株高度同源,未发现人传人的迹象,存在禽类携带及外环境污染H7N9禽流感病毒的情况。通过流行病学调查分析和病原学监测来逐步揭示H7N9禽流感病毒的流行特征和传播途径,为制定科学合理的防控策略提供依据。
Objective To analyze the etiological characteristics of the first human case of H7N9 avian influenza in Huizhou City, understand the epidemic rule of human H7N9 avian influenza, and provide the basis for making prevention and control measures. Methods The viral DNA of patients’ samples was extracted and detected by fluorescence quantitative PCR. The HA and NA gene fragments were amplified and sequenced. Active screening of cases of avian influenza A (H7N9) infection by human immunodeficiency virus (influenza) surveillance was expanded to capture the etiological surveillance of live poultry markets, poultry farms and close contacts. Results The positive rate of influenza A, H7 subtypes and N9 subtypes in respiratory specimens of the patients were compared and the phylogenetic analysis was made between the hemagglutinin and neuraminidase genes. The results showed that the HA gene of H7N9 avian influenza virus was associated with NA gene and Published human H7N9 avian influenza virus sequences are highly homologous. None of the 96 close contacts were found to be infected with the H7N9 bird flu virus. Through intensive surveillance of influenza, 274 cases of severe acute respiratory infection were found and 4 cases of H7N9 bird flu were found. 3 samples of H7N9 avian influenza virus were detected positive in the external environment of live poultry market and poultry samples. Conclusion The sequence of HA and NA genes of the first case of H7N9 bird flu in Huizhou is highly homologous with the domestic popular virus strains. There is no sign of human transmission, and there are cases of H7N9 avian influenza virus carried by poultry and external environment. Through the epidemiological investigation and analysis and etiological monitoring to gradually reveal the epidemiological characteristics and transmission of H7N9 avian influenza virus, so as to provide scientific basis for the development of a scientific and rational prevention and control strategy.