Bronchitis is either an infection or inflammation of the lining of the bronchial tubes which carry air from the windpipe to the lungs.
Pneumonia is an infection of the lungs where the air sacs become congested.
These illnesses can be caused by bacteria viruses or fungi. Chemicals or dust may also be the cause. Symptoms include cough, fever, chest discomfort, pleurisy and shortness of breath. Many bacteria and viruses are contagious. The risk of spreading these infections to otherwise healthy people is small.