Respiratory Syncytial Virus
- epidemiology
- classification and characteristics
- transmission and infection
- pathogenicity and virulence
- clinical manifestations
- diagnosis
- treatment
Epidemiology
- causes winter epidemics and sporadic causes throughout year
- almost all children infected by age of four
Classification and Characteristics
- paramyxovirus
- single stranded negative RNA
- some proteins block IF-alpha
Transmission and Infection
- transmitted by hand contact and by droplets to lesser extent
- 2-8 day incubation
Pathogenicity and Virulence
after reploicating in nasopharynx, can invade bronchiolar epithelial cells and affect Type I and II pneumocytes.
RSV kills pneumocytes, leading to sloughing and mucus production. This, coupled with inflammation can lead to bronchiole blockage, especially in children.
Partial blockage can lead to air trapping and hyperexpansion as air can enter the lungs but not leave.
Clinical Manifesations
most common cause of bronchiolitis in children
causes common cold in older kids and adults
cough
low-grade fever
can have occasional otitis media
can also get lower respiratory infections
can also lead to reactive airway disease in later years
can be fatal in premature and children with heart and lung disease
Diagnosis
chest X-ray can show airtrapping, peribrnachial thickening, atelectasis, increased linear markings
Treatment
- Palivizumab is dosed once monthly prophylactically for the season
- bronchodilators can be used
- one of few treatable virus infections; ribavirin is expensive, requires hospitalization, and reserved for only most severe hospitalizations