Respiratory Syncytial Virus - Research Paper Example

? Respiratory Syncytial Virus Respiratory Syncytial Virus Respiratory syncytial virus is one of the most important causes of bronchiolitis and pneumonia in infants. It is also a major cause of otitis media in children. It is common in children younger than two years and along with parainfluenza virus, it is the chief cause of hospitalization for respiratory tract infections in children. In United States, statistics of 1980 showed that 100,000 children were hospitalized due to respiratory syncytial virus per year (Hall, 2001). The mortality rates estimated among the Intensive Care unit patients was 8.6% (Paes et al 2011). The high incidence and mortality rate of RSV emphasizes on gaining thorough knowledge regarding its epidemiology, transmission, causes, disease progression, treatment, preventions and outcomes. Respiratory Syncytial virus is a genome RNA virus and belongs to the family paramyxovirs. It has fusion proteins on its surface that allow the virus to fuse the host cells forming multinucleated giant cells called syncytia. Humans are the natural hosts and it has two main serotypes which include subgroup A and subgroup B. Transmission of the virus is via respiratory droplets and also by direct contact of infected hands with nose or mouth (Levinson, 2008). The infections are commonly initiated during the winter season from October to December and end of March to May. RSV A causes more clinically significant diseases than B and is also more common. The children are susceptible to re-infection throughout life, however it is less clinically severe then (Paes et al 2011). Infants are considered at a high risk for the infection because of the immunopathogenic mechanism in infants. Maternal antibodies are passed to the neonates and they may react with the virus leading to formation of immune complexes. These immune complexes damage the respiratory tract cells (Levinson, 2008). Premature infants are at a higher risk for developing RSV and also require hospitalization. General population risk for hospitalization at one year of age is 2% while premature infants have a risk of 10% of requiring hospitalization with supportive care. Low birth weight is another risk for developing RSV infection at birth. Other important risk factors for the RSV infection include birth in first one-half of the RSV-season, crowded house environment, going to day-care or siblings visiting day-care, smoke exposure, breastfeeding, family history of atopy and pre-school-age siblings. Children with congenital heart diseases, neuromuscular diseases, trisomy 21, cystic fibrosis and immunodeficency states increase the complications of the RSV virus increasing the rate of hospitalization (Paes et al 2011). The RSV has an incubation period of 2-8 days and completes its replication process in the nasopharyngeal mucosa. The virus spreads from there to the lower respiratory tracts approximately three days later. The bronchiolitis caused by RSV is due to inflammation of the epithelium and leads to sloughing of the epithelial layer, edema, and increased mucous secretions. The inflammatory reactions lead to obstruction of the airway. The child presents with hyperinflation, wheezing and signs of atelactasis. Pneumonia is characterized by areas of interstitial infiltration, consolidation and alveolar filling (Hall, 2001). Expiratory wheeze is more prominent and the obstruction of air leads to air trapping in the lungs causing hyperinflation on chest radiographs. The presence of elevated serum IgA antibodies to RSV fights the infection (Long et al 2012). Bronchiolotis manifests the late stage of the respiratory disease and progresses over a period of several days. Mild cough and nasal discharge are the main symptoms after the onset of infection. 40% of patients progress and there is involvement of the lower respiratory tract as well and these patients have increased difficulty in breathing, tachypnea, wheezing, crackles, use of accessory mucles and nasal flaring (Long et al 2012). If the respiratory signs do not improve and the child continues to show signs of intercostal recessions, nasal flaring and poor oxygen saturation, then the child is shifted to intubation and ventilatory support. The median duration of symptoms in children who were previously healthy and developed bronchiolitis for the first time is estimated as 15 days and the pulmonary dysfunctions can persist for several weeks (Long et al 2012). Various therapies have been tried for the RSV infections and they have been tested through clinical trials. RSV can be treated with aerosolized ribavirin. This therapy is recommended only for hospitalized infants. Ribavirin helps in improving the oxygenation of children and reduces the inflammatory mediators caused wheezing and mucous secretions. Intravenous and inhaled human immunoglobulin is also effectively used among limited number of diseased cases. Monoclonal antibody has also been therapeutically applied. Ribavirin use is relatively restricted due to its expensive nature and limited therapeutic outcomes (Hall, 2001). Various randomized control trials have exhibited that the use of ribavirin. These trials have revealed that usage of leukotrienes, corticosteroids, inhaled bronchodilators and antibiotics do not improve the outcome. However, epinephrine and dexamethasone have shown to improve the symptoms of bronchiolitis in children. But the mainstay of treatment for RSV infection is considered to be supportive treatment which includes fluid and electrocyte balance, oxygenation and nutritional supprort (Paes et al 2011). Respiratory syncytial virus is a highly contagious virus that spreads rapidly among families, in hospital settings, day-care centers and schools. The virus can survive up to 7 hours on gloves, paper tissues, countertops and clothes and for a maximum period of thirty minutes on human skin (Abadesso et al 2004). Hence, RSV not only spreads through respiratory droplets and through touching the contaminated hands but also through fomites. Infected insects contain very high concentrations of RSV in their nasal discharge, more than 1000000/mL. The concentration of the virus comes down to lower levels over a period of thirteen days very slowly (Goldmann, 2001). It has been proved over time that infection control policies such as hand washing, gowns, gloves and cohort nursing did not help a lot in controlling the RSV outbreaks. Since infected children shed virus for two to three weeks, it is important to prevent the spread of the disease among other children especially in NICU settings and among high-risk infants. There is no vaccine currently recommended for RSV however passive immunity can be given via palivizumab (Levinson, 2008). Palivizumab has been approved for administration among high-risk infants. It is recommended in children and infants with chronic lung disease, low birth weight, premature babies and low-birth weight or premature babies born during the RSV season (Abadesso et al 2004). However, simple techniques such as hand-washing, wearing gowns and gloves while touching contaminated surfaces and other barrier techniques have also proved to be effective in lowering the incidence rates (Goldmann, 2001). The prognosis of RSV infection in previously healthy children is fairly good and they recover within weeks. However, the pulmonary function abnormalities persist. It is estimated through studies that children with RSV infection have an increased risk of developing childhood asthmas. It is shown that recurrent wheezing is higher in such infants and small-airway infections are also increased during school-going ages (Long et al 2012). Children with pre-existing morbidities such as neuromuscular, cardiac, chronic lung disease and chromosomal abnormalities develop complications after their period of hospitalization and estimated mortality rate among them is from 1% to 4% (Paes et al 2011). Respiratory syncytial virus is the leading cause of lower respiratory tract infection in neonates and children. It is a highly contagious virus which spreads by respiratory droplets and fomites. The disease progression varies in previously healthy and immune-compromised patients. High risk infants are more prone to get hospitalized and receive ventilator support. Although the viral infection is highly contagious and no vaccine has been approved yet, but preventive measures can be adapted to prevent its outbreaks and spread. Passive immunization can be offered to high-risk infants for better prophylaxis. Awareness regarding simple preventive methods should be given to families, school teachers and day-care personnel so that they can also contribute towards lowering the prevalence of RSV in the infants and neonates. References Abadesso, C., Almeida, H. I., Virella, D., Carreiro, M. H., & Machado, M. C. (September 01, 2004). Use of palivizumab to control an outbreak of syncytial respiratory virus in a neonatal intensive care unit. Journal of Hospital Infection, 58,1, 38-41. Goldmann, D. A. (January 01, 2001). Epidemiology and prevention of pediatric viral respiratory infections in health-care institutions. Emerging Infectious Diseases,7, 2,249-253. Hall, C. B. (January 01, 2001). Respiratory syncytial virus and parainfluenza virus.The New England Journal of Medicine, 344, 25, 1917-28. Levinson, W. (2008). Review of medical microbiology and immunology. New York: McGraw-Hill Companies, Inc. Long, S. S., Pickering, L. K., & Prober, C. G. (2012). Principles and practice of pediatric infectious disease. Edinburgh: Elsevier/Saunders. Paes, B. A., Mitchell, I., Banerji, A., Lancto?t, K. L., & Langley, J. M. (January 01, 2011). A decade of respiratory syncytial virus epidemiology and prophylaxis: translating evidence into everyday clinical practice. Canadian Respiratory Journal : Journal of the Canadian Thoracic Society, 18, 2. Read More