Pneumonia.

Pneumonia is an illness in which the small, air-filled sacs in the lungs responsible for absorbing oxygen from the atmosphere become inflamed and flooded with fluid. Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites. Pneumonia may also result from chemical or physical irritation of the lungs or as the result of another medical illness, such as lung cancer or alcohol abuse. Symptoms associated with pneumonia include cough, chest pain, fever, and difficulty breathing. Diagnostic tools include x-rays and examination of the sputum. Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics. Pneumonia is a common illness, occurs in all age groups, and is a leading cause of death among the elderly and people who are chronically ill. Vaccines to prevent certain types of pneumonia are available. The prognosis for an individual depends on the type of pneumonia, the appropriate treatment, any complications, and the person's underlying health.

Wikipedia.