Genetic origin of avian influenza A H7N4 virus causing a case of human infection in China , 2018
10.3760/cma.j.issn.0254-5101.2018.09.004
- VernacularTitle:1例人感染H7N4禽流感病毒分子溯源研究
- Author:
Fei DENG
1
;
Jiefu PENG
;
Lunbiao CUI
;
Xian QI
;
Shenjiao WANG
;
Huiyan YU
;
Ke XU
;
Xiang HUO
;
Changjun BAO
Author Information
1. 江苏省疾病预防控制中心
- Keywords:
Avian influenza A virus;
H7N4 subtype;
Cross-species transmission
- From:
Chinese Journal of Microbiology and Immunology
2018;38(9):665-672
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyze the molecular characteristics and genetic origin of a novel avian influenza A H7N4 virus casuing a case of human infection in China. Methods Specimens were collected from the patient and chickens and ducks kept by the patient and neighbours and then detected by real-time quantitative PCR. The original specimens and virus isolates were analyzed by next-generation sequencing technology to obtain viral whole-genome sequences. Pairwise sequence alignments and phylogenetic analysis were performed by BLASTs,ClustalX and MEGA 6. 1 softwares. Results In January 2018, a human case infected with avian influenza A H7N4 virus was confirmed. Seven H7N4 viruses were isolated from speci-mens collected from chicken and ducks kept in the patient`s backyard. H7N4 virus was a novel reassortant vi-rus with all eight gene fragments derived from wild waterfowl in Eurasia. HA protein contained a single basic amino acid residue R in cleavage site, suggesting that H7N4 virus was low pathogenic. The receptor-binding sites of HA had QSG at 226-228 residues, which indicated that the virus retained avian-type receptor speci-ficity (SAα2-3Gal). Different from H7N4 viruses in avian, the virus isolated from the patient had substitu-tion at position 627 ( E→K) in PB2 protein, which might increase its adaptation in human host. Conclusion This study reported a case of human infection with a novel reassortant avian influenza A H7N4 virus, which revealed that the traditional backyard breeding models might facilitate cross-species transmission of avian in-fluenza viruses in southern China.
