Molecular epidemiology of respiratory syncytial virus in hospitalized children in Tunisia

Abstract

Introduction: Respiratory Syncytial virus (RSV) is the most frequently identified viral agent in children with lower respiratory tract infection (LRTI). No data are available to date about RSV genotypes circulating in Tunisia. Aim and Objectives: The aim of the present study was to investigate the genetic variability of the glycoprotein G (GPG) gene in RSV strains prevalent in Tunisia. Methods: Nasopharyngeal aspirates (NPA) were collected from hospitalized infants and neonates with LRTI. All specimens were screened for RSV by Direct Immunofluorescence Assay (DIFA). To understand the evolution and origin of these strains, a phylogenetic analysis was conducted. Randomly selected positive samples were subjected to reverse transcription polymerase chain reaction (RT-PCR) amplifying the second hyper-variable region (2nd HVR) of the G gene of RSV. Results: Among a total of 427 samples collected between 2016 and 2017, 156 (36.5%) were positive for RSV by DIFA. Analysis of 21 randomly selected RSV strains revealed that Group A RSV (66.7%) predominated during the study as compared to group B RSV (33.3%). The phylogenetic analysis showed that 92.9% of the RSV-A sequences possessed a 72-nucleotide (nt) duplication in the 2ndHVR of the G gene and clustered ON1 genotype, while 7.1% clustered NA1 genotype. Concerning Tunisian RSV group B strains, all sequences contained a 60-nt insertion in the 2ndHVR and clustered genotype BA10. Conclusion: Since viruses continuously evolve, continued surveillance of RSV strains circulating worldwide is required to aid in the development of reliable diagnostics and future RSV therapeutics or vaccines.