Molecular epidemiology and phylogenetic analysis of human respiratory syncytial virus type B in Riyadh, Saudi Arabia.

Abstract

The human respiratory syncytial virus (HRSV), recently known as the human orthopneumovirus (HOPV), continues to generate new variants with the ability to cause recurrent infections. Data regarding HRSV-B evolution and genetic diversity in Riyadh, Saudi Arabia, are very limited. Therefore, the current study was designed to investigate the prevalence, genetic diversity, and evolution of HRSV-B. A total of 200 nasopharyngeal aspirate (NPA) samples from hospitalized children at King Khaled University Hospital were screened for the presence of HRSV-B. The second hypervariable region (2nd HVR) of the G gene from all 37 HRSV-B genotypes was used to study sequences and family trees. Of the 200 screened nasopharyngeal samples (NPAs), 16 (8%) were positive for HRSV-B, with a high incidence rate in the age group of 2 to 5 months. The analysis of the 2nd HVR region's sequence showed several differences, such as point mutations, different protein lengths, sequence gaps, duplication regions, and glycosylation sites. A total of 46-point mutations were reported, of which 29 changed their corresponding amino acid residues. N-linked glycosylation sites in Riyadh strains were 3, whereas O-linked glycosylation sites ranged from 22 to 32. Phylogenetic analysis revealed that Riyadh strains from the seasons 2019/20 and 2022/23 are grouped into the subclade BA-11. Other Riyadh strains from different previous seasons were clustered into different sub-genotypes (BA-9, -10, and -12). Seasonal surveillance and molecular evolution tracking of HRSV-B is essential for the early detection of viral genotypes that might cause severe illness consequences and widespread transmission.