Which term refers to the cause of a disease?

• A. Etiology
• B. Epidemiology
• C. Pathology
• D. Diagnosis

Answer: (A)

Etiology refers to the cause or origin of a disease. It explains why a disease occurs, whether due to an infectious agent, genetic factors, environmental exposures, or a combination of these. This is different from epidemiology, which studies how diseases spread and occur in populations; pathology, which looks at the structural and functional changes in tissues caused by disease; and diagnosis, which is the process of identifying the disease in a patient. For example, the etiology of tuberculosis is infection with Mycobacterium tuberculosis, and knowing that helps guide appropriate treatment and public health actions.