Leading cause of lower respiratory tract infection in infants and young children

Suspected cause of fatal respiratory diseases in infants

Almost exclusively affects infants (ages 1 to 6 months, peaking between ages 2 and 3 months) and young children, especially those in day-care settings

May cause serious illness in patients with underlying cardiopulmonary disease

Common characteristics: rhinorrhea, low-grade fever, tachypnea, shortness of breath, cyanosis, apneic episodes, and mild systemic symptoms accompanied by coughing and wheezing

Also known as RSV

Virus attaches to cells, eventually resulting in necrosis of the bronchiolar epithelium; in severe infection, peribronchiolar infiltrate of lymphocytes and mononuclear cells occurs.

Intra-alveolar thickening and resultant fluid fills the alveolar spaces.

Airway passages narrow on expiration, preventing air from leaving the lungs and causing progressive overinflation.

Probably spread to infants and young children by school-age children, adolescents, and young adults with mild reinfections

Reinfections are common, typically producing milder symptoms than the primary infection