illness is a general term that refers to a state of being unwell or feeling sick. An illness can be caused by many different factors, including infections, injuries, or underlying medical conditions. Symptoms of an illness may include fever, cough, headache, body aches, fatigue, or loss of appetite.
A disease, on the other hand, is a specific medical condition that is caused by one or more underlying factors. Diseases are usually characterized by specific signs and symptoms, and they often have known causes and risk factors. Examples of diseases include diabetes, cancer, and heart disease. Diseases can often be diagnosed and treated by healthcare professionals, whereas an illness is more of a general term that could be used to describe any number of different conditions.