Google
Power of Information
Disease
.co.nr
         

 

 










Disease is a sickness of the body or the mind. A disease can be as mild as a sore throat or as serious as a heart attack. Diseases can strike almost any part of the body. They can also affect a person's mental and emotional health.

Diseases have killed or disabled more people than all the wars ever fought. Each year, tens of millions of people die from diseases. Millions more survive serious diseases, such as cancer or strokes, but may be left permanently disabled. Countless others have mild diseases, such as colds or earaches, and recover.

Many diseases are caused by tiny living things, such as bacteria or viruses, that invade the body. These tiny objects are commonly called germs, but scientists refer to them as microorganisms. The diseases caused by these objects are called infectious diseases.

All other diseases can be grouped together as noninfectious diseases. Noninfectious diseases have many causes. Some are caused by substances that harm or irritate the body, such as cigarette smoke or traffic fumes. Others result from not eating a balanced diet. Worry and tension can lead to headaches, high blood pressure, and other illnesses. Still other noninfectious diseases occur simply because aging affects some of the body's parts.

 

Infectious diseases

Infections are the most common type of disease. Many kinds of bacteria, viruses, and other microorganisms can invade the human body and cause disease. Disease-causing microorganisms are called pathogens. Pathogens take over some of the body's cells and tissues and use them for their own growth and reproduction. In the process, they damage or destroy the cells and tissues and so produce diseases.

Infectious diseases can be grouped according to the kind of pathogen that causes them. Bacteria and viruses are the most common pathogens. But fungi, protozoans, and worms also can cause infectious diseases.
(Source: World Book)