pneumonia is an infection of one or both lungs which is usually caused by bacteria viruses or fungi. prior to the discovery of antibiotics one-third of all people who developed pneumonia subsequently died from the infection. currently over 3 million people develop pneumonia each year in the united states. over a half a million of these people are admitted to a hospital for treatment. although most of these people recover approximately 5% will die from pneumonia. pneumonia is the sixth leading cause of death in the united states.
what is pneumonia?