Pneumonia is an infection of the lungs, usually caused
by viruses or bacteria. A person with pneumonia may have a fever and cough, and it may be hard to breathe
for a little while. A doctor can tell you have pneumonia by listening to your lungs
or looking at a chest X-ray. Pneumonia can be serious, so sometimes a person who has
pneumonia has to go to the hospital. But in most cases, a doctor can treat pneumonia
while a person gets better at home.