Tell what types of microorganisms are divided by their effect on the human body.

A person is surrounded by microorganisms throughout his life. They are in the air, in water, in soil, on all objects, including food products. Microbes live and multiply on the skin, in the mouth and nose, on the mucosa of the upper respiratory tract, in the intestines.
All these microorganisms are divided into three types:
• saprophytes are microorganisms harmless to humans; getting into the human body, they never cause disease;
• conditionally pathogenic microbes, which, getting into the internal environment of a person, for the time being do not cause serious changes; but if the human body is weakened as a result of a serious injury, a long illness, or other reasons, these microbes very quickly turn into health hazards;
• pathogenic microorganisms, when ingested, cause the development of an infectious disease; this always happens if the body does not have special protection called immunity.

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