You wake up one morning and find that your infant daughter is congested. At first, you don’t think too much about it because your 3-year-old son has had a cold the past few days. A day goes by and you notice that it seems like your daughter is having trouble breathing, so you go to the emergency room. They inform you that she has RSV and needs to be admitted. What is this? Why is it so serious? How is it treated?