Pneumonia is an infection of the lungs caused by bacteria, viruses, fungi or parasites. Pneumonia can affect anyone of any age. However the elderly (>65 years old) and young children are most vulnerable. Pneumonia obstructs the normal exchange of gas inside the lungs, which leads to low levels of the oxygen in the blood and impaired removal of carbon dioxide from the body. The severity of Pneumonia ranges from mild to life threatening.