Disease is a core concept in medicine and health care, influencing the choice of research agendas and clinical practice. Yet its precise meaning is contested and influenced by broader cultural and social contexts, including ethical debates about identity, disability, and tolerance of difference.
A disease is an illness or injury that interferes with normal body functions. Your physician diagnoses disease, typically using a combination of your medical history, physical exam and test results. A disease can be infectious, such as a cold or peptic ulcers, or non-infectious, such as Alzheimer’s disease or multiple sclerosis.
An infectious disease is caused by organisms such as viruses, bacteria, fungi or parasites that get into your body from the outside world and multiply there. You can catch them by breathing in germs (like those from someone who has a cold or flu), from bug bites or through contaminated food or water. Many diseases spread from person to person, while others stay dormant in our bodies for years before becoming active again, like the varicella zoster virus that causes chickenpox and herpes zoster.
A genetic disease is one that results from a mutation in your genes. This may be inherited from parents, as in the case of Down syndrome, or it can occur spontaneously. Some diseases, such as Parkinson’s disease or rheumatoid arthritis, progress slowly over time, while others accelerate until they cause serious debility or death. A cure means the end of a disease, and remission is a temporary absence of symptoms.