Human respiratory syncytial virus
Human respiratory syncytial virus (RSV) causes respiratory tract infections. It is the major cause of lower respiratory tract infection and hospital visits during infancy and childhood. There is no vaccine, and the only treatment is oxygen.
In temperate climates there is an annual epidemic during the winter months. In tropical climates, infection is most common during the rainy season.
In the United States, 60% of infants are infected during their first RSV season[1], and nearly all children will have been infected with the virus by 2-3 years of age[1]. Natural infection with RSV does not induce protective immunity, and thus people can be infected multiple times. Sometimes an infant can become symptomatically infected more than once even within a single RSV season. Severe RSV infections have increasingly been found among elderly patients.
RSV is a negative-sense, single-stranded RNA virus of the family Paramyxoviridae, which includes common respiratory viruses such as those causing measles and mumps. RSV is a member of the paramyxovirus subfamily Pneumovirinae. Its name comes from the fact that F proteins on the surface of the virus cause the cell membranes on nearby cells to merge, forming syncytia.
Presentation
As the virus is ubiquitous in all parts of the world, avoidance of infection is not possible. Epidemiologically, a vaccine would be the best answer. Unfortunately, vaccine development has been fraught with spectacular failure and with difficult obstacles. There is much active investigation into the development of a new vaccine, but at present no vaccine exists. However, palivizumab (brand name Synagis), a moderately effective prophylactic drug is available for infants at high risk. Palivizumab is a monoclonal antibody directed against RSV surface fusion protein. It is given by monthly injections, which are begun just prior to the RSV season and are usually continued for five months. RSV prophylaxis is indicated for infants that are premature or have either cardiac or lung disease, but the cost of prevention limits use in many parts of the world.
Prophylactic treatment may be provided by intravenous RSV-IGIV infusion.[4]
Treatment
Treating respiratory syncytial virus bronchiolitis "remains a good example of therapeutic nihilism—nothing works except oxygen." Adrenaline, bronchodilators, steroids, and ribavirin confer "no real benefit."[5]
Treatment is supportive care only with fluids and oxygen until the illness runs its course.[4]
Recent studies with hyper tonic saline have shown "The use of nebulized 3% HS is a safe, inexpensive, and effective treatment for infants hospitalized with moderately severe viral bronchiolitis." Where,"Respiratory syncytial virus (RSV) accounts for the majority of viral bronchiolitis cases" [6]