ABSTRACT
Objective:To analyze the molecular characteristics of hemagglutinin-neuraminidase (HN) gene of human parainfluenza virus type 3 (HPIV3) among the cases with acute respiratory tract infection (ARI) in Henan Province.Methods:Nasal/throat swab samples collected from patients with severe acute respiratory tract infection (SARI) in Luohe and patients with influenza-like illness (ILI) in Zhengzhou were used in this study. HPIV nucleic acids in the samples were detected using real-time fluorescent PCR. HPIV3-positive samples were subjected to RT-PCR for the amplification of HN genes and the sequences were analyzed with Sanger method. CExpress and MEGA7.0 software were used for sequences editing, evolution tree construction and gene sequence analysis.Results:A total of 374 throat swab samples collected form ARI cases in Luohe and Zhengzhou were tested and 20 (5.3%) of them were positive for HPIV3. Eighteen HPIV3 HN gene sequences were successfully amplified and all belonged to C3 subgroups, including 16 sequences of C3f genotype and two sequences of C3a genotype. The 18 HN gene sequences shared the homology of 97.6%-100.0% in nucleotide and 99.3%-100.0% in amino acid, but the differences between them and the prototype strain Wash/47885/57 were significant. There were 12 amino acid mutations shared by them, including four function-related mutations (H295Y, I391V, D556N and I53T). There were no significant differences in the nucleotide or amino acid sequences as compared with the epidemic strain of China/BCH4210A/2014.Conclusions:The C3f and C3a branches of HPIV3 were the epidemic genotypes in Henan Province in recent years and a local circulating prevalence might be established. Continuous and in-depth monitoring of HPIV3 C3 subtype would be of great significance for the prevention and control of HPIV3-associated diseases.