长沙市1例人感染H3N8禽流感病例的流行病学调查和病原学分析

目的 了解人感染H3N8禽流感病例的流行病学特征和临床特征及其病原的分子生物学特征,为人感染H3N8禽流感防控提供科学依据。方法 采用流行病学调查方法对长沙市2022年5月1例人感染H3N8禽流感病例的可疑暴露史、感染途径、发病及就诊经过,以及密切接触者、可疑暴露者等涉疫重点人员进行现场调查,并进行描述性分析;采用核酸检测和基因测序技术,进行病原学检测和基因特征分析。结果 病例发病前6 d有活禽交易市场暴露史,在活禽交易市场、活禽来源批发市场均检测出禽流感H3、N8亚型阳性。深度基因测序显示,病毒对哺乳动物发生适应性突变,对烷胺类药物敏感性降低,未检测到神经氨酸酶抑制剂类药物和聚合酶抑制剂类药物相关的耐药性突变。结论 病例暴露于被H3N8禽流感病毒污染的活禽交易市场环境而感染,未发现人际间传播。

Epidemiological investigation and etiological analysis on a case of human infection with avian influenza A (H3N8) virus in Changsha

Objective To understand the epidemiological and clinical characteristics of human infection with avian influenza A(H3N8) virus and the molecular biological characteristics of the pathogen, and provide scientific evidence for the prevention and control of human infection with avian influenza A(H3N8) virus. Methods An epidemiological investigation was conducted for a case of human infection with avian influenza A(H3N8) virus in Changsha in May 2022 to collect the information about exposure history, route of infection, onset and treatment, potential contacts and other possible exposures for a descriptive analysis. Nucleic acid detection and gene sequencing were used to detect the pathogen and analyze the genetic characteristics. Results The case had a history of exposure to live poultry trading market 6 days before the onset of illness. Subtypes H3 and N8 of avian influenza virus were detected in live poultry markets. Deep gene sequencing showed that the virus had adaptive mutations in mammals, reduced sensitivity to alkamine agent, and no resistance mutations related to neuraminidase inhibitors and polymerase inhibitors were detected.Conclusion The case was infected due to exposure to the live poultry market environment contaminated by avian influenza A(H3N8) virus, and no human to human transmission was found.