Pneumonia is a serious infection of the lungs that causes the air sacs in the lungs to fill with pus and other liquid. The infection may be caused by any of the following causative agents: bacteria, virus, fungi, mycoplasma, or chemicals. In general, pneumonia is divided into two types: community-acquired or hospital or nursing home-acquired.

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You may get pneumonia simply because you encounter an organism that you breathe into your lungs. Whether or not you get sick depends on the contagiousness of the organism, the number of organisms you inhaled, and the ability of your immune system to fight infections. Or, you may have another infection, which travels through your bloodstream to infect your lungs. (This is very rare, however.)

In the United States, pneumonia is a very common illness, with about 5 million cases occurring every year. The economic burden for the nation is approximately $39 billion a year. Over 67,000 Americans die each year from pneumonia, making pneumonia the eighth most common cause of death in the US.

What are the risk factors for pneumonia?
What are the symptoms of pneumonia?
How is pneumonia diagnosed?
What are the treatments for pneumonia?
Are there screening tests for pneumonia?
How can I reduce my risk of pneumonia?
What questions should I ask my doctor?
Where can I get more information about pneumonia?