To evaluate the effect of respiratory syncytial virus (RSV) infection on the response to laryngeal chemostimulation (LCS) with water, five lambs were inoculated with human RSV and three lambs were given control media at an age of 3-5 days. During RSV infection, LCS resulted in increased inhibition of minute ventilation and delayed recovery of regular breathing. Sleep further increased the response, and arousal was less likely to occur in active sleep. Two of the five infected lambs needed resuscitation after LCS when arousal was absent. Histological studies showed bronchiolitis and pneumonitis. Laryngeal tastebud morphology was unchanged at 8 days after inoculation. However, infected lambs had disrupted tastebuds 4-6 weeks after infection. Failure to arouse and to terminate reflex apnea may play a role in the pathogenesis of the sudden infant death syndrome associated with respiratory tract infection.