A disease is an abnormal condition of an organism that impairs bodily functions. In human beings, "disease" is often used more broadly to refer to any condition that causes discomfort, dysfunction, distress, social problems, and/or death to the person afflicted, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories. This article primarily describes human diseases, one of man's greatest enemies. While many diseases are biological processes with observable alterations of organ function or structure, others primarily involve alterations of behavior. Classifying a condition as a disease is a social act of valuation, and may change the social status of the person with the condition . Some condition More »