There are many different types of diseases that affect humans, animals, and plants. Diseases can be caused by viruses, bacteria, fungi, parasites, or other microorganisms. Some diseases are hereditary, while others are caused by environmental factors.
Infectious Diseases
Infectious diseases are caused by the spread of germs, such as viruses or bacteria, from one person to another. These diseases can be spread through contact with an infected person, through contact with contaminated surfaces or objects, or through the air. Examples of infectious diseases include the common cold, influenza, measles, and chickenpox.
Non-Infectious Diseases
Non-infectious diseases, sometimes referred to as non-communicable diseases, are not caused by the spread of germs. These diseases are usually caused by lifestyle factors, such as smoking, poor diet, and lack of exercise. Examples of non-infectious diseases include heart disease, stroke, cancer, and diabetes.
Autoimmune Diseases
Autoimmune diseases are caused when the body’s immune system mistakenly attacks healthy cells in the body. These diseases can affect any part of the body, and can cause a wide range of symptoms. Examples of autoimmune diseases include rheumatoid arthritis, lupus, and multiple sclerosis.
Genetic Diseases
Genetic diseases, sometimes called inherited diseases, are caused by a defect in an individual’s genes. These diseases are usually passed down from parents to children, though some may be caused by a spontaneous mutation. Examples of genetic diseases include cystic fibrosis, sickle cell anemia, and Huntington’s disease.