In any disease, the person falls ill but the ways in which the illness shows, e.g. headache, vomiting, fever, etc. are different. These are called symptoms and they are characteristics of a particular disease, for e.g. gastric trouble in gastroenteritis.
Causes or factors refer to reasons for disease. They can be pollution, bad habits, poor hygiene, etc. and cure refers to the treatment of disease. All these do not characterize a disease.