An eight month old infant is brought to the hospital by her father. He states that the child has had a recent- onset of acute sore throat, fever, rhinorrhea, and hoarseness. On physical exam, the infant appears to have some difficulty breathing and is tachypneic and feverish. Diffuse wheezes and rales are present with rhonchi over the lung fields.

Labs: Immunoflourescent smears of the respiratory epithelium reveals RNA enveloped virus. There is also a greater than 4-fold increase in antibody titer.