What is Pneumonia? Detailed Insights on Symptoms, Types, and Prevention

Pneumonia is an infection in the lungs which is caused by bacteria, viruses or fungi. Pneumonia causes the lung tissue to swell and might also cause fluid or pus in the lungs. Bacterial pneumonia is usually more severe than viral pneumonia, which often resolves on its own. Pneumonia can affect one or both lungs. Pneumonia in both of your lungs is called bilateral or double pneumonia.