Respiratory Diseases

Pneumonia, another life threatening disease, is an infection or inflammation of the lungs caused by bacteria, viruses, mycoplasma (microorganisms that show similarities to both viruses and bacteria), and fungi, as well as such inorganic agents as inhaled dusts or gases. The irritation to the lung tissues from these sources destroys the alveoli (air sacs) of the lung. Blood cells from lung capillaries then fill the alveolar spaces. The affected part of the lung loses its elasticity and can no longer fulfill its vital tasks of supplying the rest of the body with oxygen and eliminating carbon dioxide gas. Symptoms of this disease include pleurisy (chest pain), high fever, chills, severe coughing that brings up small amounts of mucus, sweating, blood in the sputum (pus and mucus), and labored breathing.

Pneumonia infections are divided into two classes: in lobar pneumonia one lobe of the lung is affected, whereas bronchial pneumonia shows up as patches of infection that spread to both lungs. Pneumococcus bacteria are responsible for most bacterial pneumonia. The lobes of the lung become filled with fluid, and the bacterial infection spreads to other parts of the body. There is a vaccine for this type of pneumonia. Viruses cause about half of all the pneumonias. Influenza viruses may invade the lungs, which in this case, do not become filled with fluid. The symptoms of viral pneumonia, which are not as serious as those of bacterial pneumonia and last for shorter periods of time, are similar to those of influenza.

Mycoplasma pneumonia is not as severe as bacterial pneumonia, either. Even if untreated, this type of pneumonia is associated with a low death rate. A more recent type of pneumonia that made its appearance with the AIDS epidemic is pneumocystis carinii pneumonia (PCP). It is caused by a fungus and is often the first sign of illness a person with AIDS experiences. Other less common pneumonias are beginning to appear more frequently and require preventive measures (if possible, early detection and effective treatment). In 1936 pneumonia was the main cause of death in the United States. Since then it has been controlled by antibiotics, but as resistant strains of bacteria have developed, the number of cases has increased. In 1979 pneumonia and influenza combined formed the sixth major cause of death in the United States.