Common diseases in human beings

A disease is any disorder or malfunction of the body or mind. It can arise from environmental factors, disease-causing organisms (pathogens), genetic anomalies, or lifestyle choices, and it disturbs the body's normal structure, function, or psychological state.

Diseases fall into two broad groups:

• Infectious (communicable) diseases — caused by pathogens (viruses, bacteria, fungi, protozoan parasites or helminthic worms) that pass from an infected person to a healthy one through air, water, food, physical contact, or vectors such as insects. Most bacterial diseases can be cured, but not every viral disease can be, and a few, such as AIDS, can be fatal.
• Non-infectious diseases — not transmitted between people. These arise from genetic causes (e.g. cystic fibrosis), nutritional deficiencies (e.g. vitamin-deficiency disorders), or degenerative processes (e.g. arthritis, heart attack, stroke). Cancer is one of the leading causes of death among this group. …