A short description about Pneumonia ? Pneumonia is a lung infection that causes the air sacs in one or both lungs to become inflamed. Cough with phlegm or pus, fever, chills, and trouble breathing can occur when the air sacs fill with fluid or pus (purulent material). Pneumonia can be caused by a variety of species, including bacteria, viruses, and fungus. The severity of pneumonia can range from minor to life-threatening. Infants and young children, persons over the age of 65, and people with...