Pneumonia is a form of acute respiratory infection that affects the lungs.
It is caused by inflammation of the airspaces in the lungs.
Lungs are made up of small sacs called alveoli, which fill with air when healthy person breathes.
When an individual has pneumonia, alveoli are filled with pus and fluid, which makes breathing painful and limits oxygen intake.
It is caused by number of infectious agents, including viruses, bacteria and fungi.
The most common are Streptococcus pneumoniae (most common cause of bacterial pneumonia in children), Haemophilus influenzae type b (Hib) (second most common cause of bacterial pneumonia), Respiratory syncytial virus is most common viral cause of pneumonia.
Vaccinations are available against several common organisms that are known to cause pneumonia.
Besides, antibiotics can also treat pneumonia by controlling the bacterial or fungal infection.