Flu refers to illnesses caused by a number of different influenza viruses. Flu can cause a range of symptoms and effects, from mild to lethal.
Two strains of flu, seasonal flu and the H1N1 (Swine) flu, are currently circulating in the United States. A third, highly lethal H5N1 (Bird) flu is being closely tracked overseas.
Most healthy people recover from the flu without problems, but certain people are at high risk for serious complications.
In the U.S., epidemiologists at the Centers for Disease Control (CDC) work with states to collect, compile and analyze reports of flu outbreaks. More on the current situation.
Warning SignsFlu and Pneumonia
How do I know if I have the flu? Find out the warning signs.
Annual outbreaks of the seasonal flu usually occur during the late fall through early spring. Most people have natural immunity, and a seasonal flu vaccine is available. In a typical year, approximately 5 to 20 percent of the population gets the seasonal flu and approximately 36,000 flu-related deaths are reported.
Read more at Flu.gov: http://www.flu.gov/individualfamily/about/index.html
Pneumonia is an inflammation of your lungs, usually caused by infection. Bacteria, viruses, fungi or parasites can cause pneumonia. Pneumonia is a particular concern if you’re older than 65 or have a chronic illness or impaired immune system. It can also occur in young, healthy people.
Pneumonia can range in seriousness from mild to life-threatening. Pneumonia often is a complication of another condition, such as the flu. Antibiotics can treat most common forms of bacterial pneumonias, but antibiotic-resistant strains are a growing problem. The best approach is to try to prevent infection.
More information from the Mayo Clinic: H1N1 flu