Virus Reviews and Research Sociedade Brasileira de Virologia journal homepage: www.sbv.org.br/vrr/ Research Article RESPIRATORY SYNCYTIAL VIRUS: FROM DISCOVERY TO TREATMENT Débora C Chong-Silva, M.D., MSc * ; Nelson A Rosário, M.D., Ph.D Professor of Pediatrics - Federal University of Paraná. ABSTRACT To review the epidemiology, identication, clinical patterns and treatment of respiratory syncytial virus infection. Raised available studies in the MEDLINE database using the keywords respiratory syncytial virus, respiratory infection, bronchiolitis and indirect immunouorescence in international studies since 1980. Respiratory Syncytial Virus (RSV) was rst time isolated in 1956 and became the most frequently agent found, especially in the lower respiratory tract of children. It is responsible for signicant morbidity and mortality in children younger than 18 months with risk factors such as prematurity and heart disease. It shows well-dened distribution along the year. Histopathology, immunohistochemistry and standardized molecular techniques to identify the virus have been described. e specic treatment of RSV infection is still limited. Antiviral agents as ribavirin showed limited eectiveness and restricted to use in a few patients with severe heart disease. Vaccines needs further studies before marketed. Humanized monoclonal antibody - palivizumab - is safe, well tolerated and the most cost-eective when used in children at risk for severe RSV infection. e high rate of children hospital admissions by RSV infection is a public health issue. Treatment is yet supportive and non specic according to severity. Epidemiologic surveillance, routine virus identication and acessibility to health centers are the key points to control infection by this virus. Keywords: Respiratory syncytial virus, respiratory infection, bronchiolitis, prevention Received in January 14, 2014 - Accepted in April 8, 2014 - Published ahead of print in April 14, 2014 The Discovery In 1956 the Respiratory Syncytial Virus (RSV) was identied for the rst time from upper airway secretion of chimpanzee monkeys with bronchiolitis symptoms. It was known as the chimpanzee coryza agent (Chanock et al. 1957). At the same time some cases of airway infections in humans were associated to this agent, especially lower airway infection in children. In 1957, due to the virus characteristics, infecting the airway and generating gigantic syncytial cells in tissue culture, it was renamed as Respiratory Syncytial Virus, used still nowadays (Chanock et al. 1957). Researches have conrmed its importance and frequency of the RSV involvement as a leading cause of airway infections in children worldwide. RSV belongs to the family Paramyxoviridae - as the measles virus, mumps virus, parainuenza group and more recently discovered Nipah and Hendra virus. e RSV’s subfamily is Pneumovirinae that includes the Human Metapneumovirus (hMPV) capable to create a very similar clinical presentation of the RSV, as bronchiolitis and pneumonia (Van Den Hoogen et al 2001, Lourenção et al 2005). Nonetheless, the hMPV infection is more common in children with congenital anomalies, as cardiopulmonary and it is associated to a greater ventilatory demand (Zhang et al. 2009). e RSV particles have a median size ranging from 120 to 300nm with helical symmetry (Lourenção et al. 2005). e viral nucleocapsid, also known as core, is composed of structural proteins combined with the viral genome, which is a single RNA strand. It is capable to performing at least 10 dierent types of proteins, most of them with structural function and two non- structural proteins with still unknown function (Bricks 2001). e viral genome consists of 15222 nucleotides that in association with nucleocapsid proteins, form a ribonucleoprotein complex resistant to RNAse activity (Mohapatra & Lockey 2008). e viral core is wrapped by an envelope that is formed by the plasma membrane of the host cell, composed by dierent types of glycoproteins. e Glicoprotein F and G are transmembrane proteins and * Corresponding author. E-mail address: debchong@uol.com.br