RSV

Respiratory syncytial virus (RSV) was first isolated from chimpanzees in 1956 and was subsequently recovered from infants with severe lower respiratory tract disease. RSV belongs to the family of Paramyxoviridae, genus Pneumovirus, subfamily Pneumovirinae and is a non-segmented negative-sense single-stranded enveloped RNA virus. It contains 10 genes which encode 11 proteins. Two overlapping open reading frames in the M2 mRNA yield two distinct matrix proteins, M2-1 and M2-2. The viral envelope contains three proteins. They are the G glycoprotein, the fusion (F) glycoprotein, and the small hydrophobic (SH) protein. The G protein functions in host cell attachment and the F protein is responsible for fusion and cell entry. The SH protein is not required in either of these processes. The RSV virus comprises five other structural proteins, the large (L) protein, nucleocapsid (N), phosphoprotein (P), matrix (M), and M2-1, and two non-structural proteins (NS1 and NS2).

The clinical picture of RSV infection varies according to age. The primary infection at 6 weeks to 2 years of age is usually symptomatic and involves the lower respiratory tract. Asymptomatic primary RSV infection in children is rare. Repeated infections in older children are usually less severe. Respiratory tract infections are frequently associated with expiratory wheezing