HRSV

Background: Human Respiratory Syncytial virus (hRSV) is one of the major causes of viral respiratory tract infection in infants and young children. Aim of study: The aim of this study was to determine the risk factors associated with hRSV infection. Objective: This study included 100 hospitalized infants and young children with chest infection (39 female and 61 male) aged from (1) to (24) months, their mean age (6.87) months. Material and methods: Nasopharyngeal/throat swabs specimens were collected over a three-month winter period from January to April, 2017. hRSV was determined by reverse transcription polymerase chain reaction (RT-PCR). Results: The highest percentage of hRSV RNA (56.81%) was observed in the age group less than 6 months, followed by (27.27%) and (15.91%) in the age group 6-12 months and 12-24 months, respectively, which mean that (84%) of hRSV infections were under 12 months of age. Regarding the type of feeding, about (84%) of hRSV infections were positive in patients with bottle feeding which indicated that the role of breastfeeding in preventing hRSV infection and hospitalization is undisputed. The hRSV-RNA is equally distributed between patients exposed and not exposed to smoking (50%). Conclusion: This study showed that there were no statistical significant association between risk factors under study and the occurrence of hRSV infection (P˃ 0.05).

The M2-1 protein of the important pathogen human respiratory syncytial virus is a zinc-binding transcription antiterminator that is essential for viral gene expression. We present the crystal structure of full-length M2-1 protein in its native tetrameric form at a resolution of 2.5 Å. The structure reveals that M2-1 forms a disk-like assembly with tetramerization driven by a long helix forming a four-helix bundle at its center, further stabilized by contact between the zinc-binding domain and adjacent protomers. The tetramerization helix is linked to a core domain responsible for RNA binding activity by a flexible region on which lie two functionally critical serine residues that are phosphorylated during infection. The crystal structure of a phosphomimetic M2-1 variant revealed altered charge density surrounding this flexible region although its position was unaffected. Structure-guided mutagenesis identified residues that contributed to RNA binding and antitermination activity, revealing a strong correlation between these two activities, and further defining the role of phosphorylation in M2-1 antitermination activity. The data we present here identify surfaces critical for M2-1 function that may be targeted by antiviral compounds.