Analysis of the epidemiological characteristics and the whole genome characteristics of influenza A H1N1 pdm09 virus outbreak in a school / 中国热带医学

ABSTRACT

@#Abstract: Objective　To analyze the whole genome characteristic of influenza A(H1N1) pdm09 virus outbreak in a school in Jining, so as to serve as a reference for prevention and control of influenza A (H1N1) pdm09．Methods　Real time fluorescence quantitative PCR were used to detected the 12 nasopharyngeal swab specimens from patients. The positive specimens were cultured and sequenced the whole genome. DNASTAR was used to analyze the homology. MEGA was used to construct the phylogenetic tree. NetNGly, GPS-SUMO, NetPhos were used to predict the glycosylation sites, the small ubiquitin-like modifier sites and the phosphorylation sites respectively. Results　Among of 12 specimens, 4 specimens were showed positive for influenza A (H1N1) pdm09 virus nucleic acid, and 4 virus strains were isolated. Compared to the vaccine strain A/Brisbane/02/2018, the homology of nucleic acids of 8 gene segments was 98.5%-99.8%. The homology of amino acids of 10 proteins was 98.2%-100%. In the evolutionary tree analysis, four strains were located in two evolutionary clusters, three strains in the same evolutionary cluster and one strain in a different evolutionary cluster. A total of 50 amino acid site substitutions occurred in the 10 proteins encoded by the four strains, including two amino acid sites in the hemagglutinin antigen epitope, and there was no mutation in the neuraminidase (NA) protease active site, polymerase acidic protein (PA), polymerase basic protein 1 (PB1) and polymerase basic protein 2 (PB2) inhibitor resistance sites, and neuraminidase inhibitor resistance sites. In addition, the glycosylation sites and SUMO sites were not mutated, while multiple phosphorylation sites were substituted. Conclusions　There are 2 different sources of influenza A (H1N1) virus causing the school influenza outbreak. School influenza outbreak surveillance and school influenza prevention and control should be strengthened should be enhanced.