Christen Strickler

CRA

Disease

Human Respiratory syncytial virus (RSV) infections

Causative Agents

Respiratory syncytial viruses are spherical, enveloped, single-stranded linear RNA viruses that are classified as genus pneumovirus, and part of the subfamily Pneumovirinae. RSV shares the characteristics of being a part of the family Paramyxoviridae with the Measles and Mumps viruses. During mRNA transcription, the respiratory syncytial virus creates fusion protein (F protein) that is required for fusing the virus to cells and connecting neighboring cells to create syncytia (def). The virus ranges in size from 100-350 nanometers (def). The virus can only survive on surfaces for up to six hours.

Epidemiology

Respiratory syncytial virus is found worldwide and usually appears in all children before their 2nd-3rd birthday.  RSV infections primarily affect the respiratory tract. The CDC states that this organism is the “most common cause of bronchiolitis (def) in children under 1 year of age in the United States.” It is estimated that only 2-3% of those infected will require hospitalization, or about 75,000 to 125,000 children annually. Of these incidents, approximately 4500 cases result in fatalities.

The severity of the RSV infection is greatly increased for newborn or premature infants.  Most children are infected with RSV during their first exposure season, which usually goes from November to April in the United States. This exposure period may differ in different parts of the world due to seasonal changes, for example infections are higher in tropical climates during the rainy months.

Older children and adults can experience RSV infections; however, the symptoms are usually less severe and they are more prone to be carriers of the virus and expose young children in their care. In a community outbreak study, it was found that 61% of adult healthcare workers carried an active virus.

Transmission

Respiratory syncytial viruses are a common nosocomial (def) or community-acquired infection among children. RSV is primarily spread through respiratory secretions. The virus can be transmitted through large aerosol particles or by touching objects and surfaces that have been contaminated.

Signs and Symptoms

The incubation period for RSV is usually 4 to 6 days. Initial symptoms may appear as rhinitis (def) and appetite loss. Additional symptoms of coughing, sternutation (def), pharyngitis (def), tachypnea (def) and fever can later emerge. A lot of cases, especially in adults, are asymptomatic (def). Infants may only exhibit lethargy, poor feeding and breathing difficulties.  Most children that are infected with RSV do not require hospitalization, and full recovery from the infection takes about 1-2 weeks.

In some severe cases, RSV could cause bronchiolitis (def). The most common cause for bronchiolitis (def) in children under the age of 1 is RSV. Symptoms can include coughing, wheezing, shortness of breath, and hypoxia (def). This is more common in children that are at higher risk (newborns, premature infants, immunocompromised (def) children).

Prevention and Treatment

A vaccine does not exist for respiratory syncytial virus. It is hard to prevent exposure to children as the virus is widespread and easily transmitted. It is important to take extra precautions with children who are at high risk, such as premature infants or newborns during the RSV season. These precautions can include: frequent hand washing, avoid community shared events and places, and to avoid those who have any symptoms or have been exposed.

There is currently no accepted treatment for RSV-caused bronchiolitis (def). The infected patient is given fluids and oxygen until they have recovered from the infection.
 

Bibliography

CDC. Respiratory Syncytial Virus Overview. Retrieved April 10, 2010 from http://www.cdc.gov/rsv/

Medscape. Steps to Reduce Nosocomial Infections in Children: Respiratory Syncytial Virus Retrieved April 10, 2010 from http://www.medscape.com/viewarticle/442779_4

Wikipedia. Bronchiolitis. Retrieved April 10, 2010 from http://en.wikipedia.org/wiki/Bronchiolitis

Wikipedia. Respiratory Syncytial virus. Retrieved April 10, 2010 from http://en.wikipedia.org/wiki/Respiratory_syncytial_virus