Objective To analyze genetic characteristics of human metapneumovirus (hMPV) strains isolated in Ningxia Hui Autonomous Region (Ningxia) for providing relevant data to construct hMPV genome database in China.
Methods Two hMPV strains isolated from throat swab specimens were collected from the positive sample bank of 2021 for respiratory disease pathogen monitoring in Ningxia and whole genome sequencing was performed for the two strains. Informatics analysis was conducted with 27 representative strains of hMPV genotypes downloaded from the National Biotechnology Information Center (NCBI). MEGA7.0 was used to construct phylogenetic tree and calculate genetic distance and MegAlign 7.1 in DNAStar 7.1 software package was adopted to analyze amino acid and nucleotide homology of the strains.
Results The results of phylogenetic tree of G protein genome sequencing, F protein genome sequencing and whole genome sequencing showed that the two hMPV strains belong to the same branch of B2 type. The amino acid distance (nucleotide distance) between the whole genome sequence of the two strains (hMPV/NX01/2021 and hMPV/NX02/2021) and the whole genome sequence of the Australian strain (MW221994) in 2020 are the nearest, with the distance of 0.005 (0.002) and 0.006 (0.003), respectively. The two hMPV strains had the highest homology with the average amino acid and nucleotide of hMPV-B2 in the whole genome sequence and sequences of each protein genome (N, P, M, F, M2-1, M2-2, SH, G, L).
Conclusion The genome of the two respiratory human metapneumovirus stains isolated in Ningxia region has the genetic characteristics of hMPV, and both belong to the hMPV-B2 genotype.
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