There are a few different types of bronchitis, so the type will determine how you get bronchitis. Chronic bronchitis is usually caused by smoking or other lung irritants over a long period of time. Acute bronchitis will come after any type of cold or flu virus when infection sets into the lungs. You can find more information here: http://www.nlm.nih.gov/medlineplus/ency/article/001087.htm
