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.