Bronchitis
Much like pneumonia, some forms of bronchitis are contagious and others are not: It depends on what’s causing the inflammation of the bronchial airways and the resulting coughing, wheezing, and general breathing difficulties. Acute bronchitis, which usually results from an upper respiratory infection that travels to the chest, is often caused by a virus and is contagious. Hundreds of viruses, as well as some bacteria, can potentially lead to bronchitis, and you can catch them when germs enter your mucous membranes through your eyes, nose, or mouth. Chronic bronchitis, however, isn’t contagious. This ongoing condition is often caused by long-term smoking or exposure to environmental pollutants.