short Essay on Human Diseases (482) A disease is a condition that impairs the proper functioning of the body or of one of its part.These include organ or tissue degeneration, erratic cell growth, and faulty blood formation and flow.Every disease also displays a cycle of onset, or beginning, course, or time span of affliction, and end, when it disappears or it partially disables or kills its victim.These diseases occur due to gene or chromosomal mutations, e.g. Colour blindness, thalassemia etc.Acquired diseases are of two types - Communicable diseases (Infectious) are those that can be passed among persons such as by means of airborne droplets from a cough or sneeze.The gradual onset and long course of TB makes it a chronic ailment.