Kunming National High-level Biosafety Research Center, Chinese Academy of Medical Science, Institute of Medical Biology, China.
Kunming City Center for Disease Control and Prevention, China.
Infect Genet Evol. 2018 Dec;66:152-158. doi: 10.1016/j.meegid.2018.09.022. Epub 2018 Sep 21.
Two imported family cases (mother and daughter) of fatal H7N9 infection in Kunming, China were reported in 2017. Epidemiological investigation showed that the two family members had both been exposed to sick chickens in a poultry market. The onset of illness and death of the mother was 7 days later than her daughter, raising concerns about human-to-human transmission of H7N9 in the locality. Sequence alignment and phylogenetic analysis of the virus strains isolated from the two patients revealed high sequence similarity (≥ 99%) and homology to each other. The two virus strains shared a PEIPKGR/G cleavage motif and the same key amino acid mutations across 8 viral genes except for a R292K mutation in the neuraminidase (NA) gene isolated from the mother who had been treated with oseltamivir in the clinic. Moreover, the isolated H7N9 virus possesses avian and human dual-receptor specificity and is able to efficiently proliferate in human cell lines in vitro. Further epidemiological study demonstrated that five family members who had close contacted with the patients were free of illness and negative for the H7N9 genomic test. Collectively, the H7N9 virus described here is still limited to transmit efficiently from human-to-human.
2017 年，中国昆明报告了两例输入性家庭（母女）感染致命 H7N9 病例。流行病学调查显示，两名家庭成员均曾接触过农贸市场上的病鸡。母亲的发病和死亡时间比女儿晚 7 天，这引起了人们对当地 H7N9 人际传播的关注。对两名患者分离的病毒株进行序列比对和系统进化分析显示，病毒株之间的序列高度相似（≥99%），彼此同源。两株病毒株均具有 PEIPKGR/G 裂解基序和 8 个病毒基因的相同关键氨基酸突变，但母亲体内分离的神经氨酸酶（NA）基因存在 R292K 突变，该母亲曾在临床上接受过奥司他韦治疗。此外，分离的 H7N9 病毒具有禽源和人源双重受体特异性，能够在体外高效增殖人细胞系。进一步的流行病学研究表明，与患者密切接触的 5 名家庭成员未患病，且 H7N9 基因组检测均为阴性。综上所述，这里描述的 H7N9 病毒仍仅限于在人与人之间有效传播。
