Pneumonia is a lung infection affecting the air sacs that makes it difficult to breathe. Learn what causes this condition, how to treat it, and more. The symptoms of pneumonia can range from mild to severe, and include cough, fever, chills, and trouble breathing. Many factors affect how serious a case of pneumonia is, including what caused the infection, the person's age, and their overall health. Pneumonia is an infection of the lungs caused by bacteria, viruses, fungi, or parasites. Read on for more about the risk groups and treatments available. Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. [3][14] Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. [15] The severity of the condition is variable. [15] Pneumonia is usually caused by infection with viruses or bacteria, and less commonly by other microorganisms. [a] Identifying the responsible pathogen can be difficult. Diagnosis is often based on symptoms and ...
