Molecular epidemiology of human respiratory syncytial virus with severe acute respiratory infection in Huzhou from 2016 to 2019

BackgroundHuman respiratory syncytial virus (HRSV) is one of the major cause of acute lower respiratory infection in infants, the elderly and people with low immunity worldwide. Based on antigenic and genetic variations, Human respiratory syncytial virus is divided into two subgroups (A and B). Each of the subgroups is further categorized into genotypes based on the phylogenetic analyses of the sequences of the second hypervariable region. MethodsNasopharyngeal swabs (NPSs) were collected from patients of the First Peoples Hospital in Huzhou from January 2016 to December 2019. Real-time RT-PCR (qPCR) was performed using double nucleic acid detection kit for respiratory syncytial virus (A\B) (Shenzhen shengkeyuan) with the ABI Q7 (Applied Biosystems). For genotyping, the primer set A-F/A-R was used to amplify the G protein of HRSV-A. Primer set B-F/B-R was used to amplify the G protein of HRSV-B. The phylogenetic analysis was constructed using the neighbor-joining algorithm with the Kimura two-parameter model and supported statistically by bootstrapping with 1000 replicates with MEGA software (version 7.0) with 1000 bootstrap replicates. ResultsA total of 973 nasopharyngeal swab samples were collected from January 2016 to December 2019, and 63 samples were positive for RSV nucleic acid, with the detection rate of 6.47%. Of the positive specimens, 28 were belonged to HRSV-A, and 35 were belonged to HRSV-B. Infection with RSV was found in all age groups tested, with the 0-1 year age group having the highest detection rate 15.2%. The detection rate was high from November to next March. Phylogenetic analysis clustered HRSV-A strains identified in Huzhou into ON1genotype. All 17 of the HRSV-B strains belonged to BA9 genotype. ConclusionsWe analyzed the HRSV strains circulation in Huzhou from January 2016 to December 2019 in Huzhou, China. This is the first molecular analysis on HRSV in Huzhou. We found Subgroup A and B of RSV were co-circulating and the 0-1 year age group having the highest infection rate.