Human diseases are conditions that affect the normal functioning of the body. They can be caused by various factors, including infections from bacteria, viruses, or fungi, genetic mutations, and environmental influences. Diseases can be acute, meaning they occur suddenly and last a short time, or chronic, lasting for a long period and often requiring ongoing management. Common human diseases include diabetes, heart disease, and cancer. Symptoms can vary widely, ranging from mild discomfort to severe pain and disability. Prevention and treatment options depend on the specific disease and may involve lifestyle changes, medications, or medical procedures.