Respiratory syncytial virus infection results from a subgroup of the myxoviruses that resemble paramyxoviruses. The organism is transmitted from person to person by respiratory secretions and has an incubation period of 4 to 5 days.

Reinfection is common, producing milder symptoms than the primary infection. School-age children, adolescents, and young adults with mild reinfections are probably the sources of infection for infants and young children.

Young children, especially infants, are at increased risk for severe infection. Common complications include pneumonia, bronchiolitis, tracheobronchitis, and otitis media. Acute complications include apnea and respiratory failure.

Signs and symptoms vary in severity. The patient may complain of nasal congestion, coughing, wheezing, malaise, sore throat, earache, dyspnea, and fever. Although uncommon, signs and symptoms of central nervous system infection, such as weakness, irritability, and nuchal rigidity, also may be observed.

Inspection usually reveals inflamed mucous membranes in the nose and throat. Other findings are variable. For example, with otitis media, you may see a hyperemic eardrum on otoscopic examination; with severe respiratory distress, you may note nasal flaring, retraction, cyanosis, and tachypnea. With a lower respiratory tract infection, you may hear or auscultate wheezes, rhonchi, and crackles.