A 5 month-old boy is admitted to the hospital with a 24-hour history of choking spells. These began with repeated coughing where he turned red and gasped for breath. In the previous 2 days he also had two episodes of vomiting. The baby was found to have an increased breathing rate, which was difficult, but his chest x-ray showed no evidence of pneumonia. Blood work showed an abnormally large percentage of lymphocytes (70%). Nasopharyngeal swabs cultured grayish, "mercury-like" colonies, and a Gram stain revealed minute Gram negative coccobacilli.
A. What is wrong with the baby? What led you to this diagnosis?
B. Is this an unusual disease for a child to have? Could it have been prevented?