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Definition of Pathogen

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Updated March 20, 2009

Definition: A disease-causing agent.

Most pathogens are infectious microbes, such as bacteria or viruses, which are capable of causing disease. Other parasites, such as fungi and protozoans, are also considered pathogens. Because not all microbes are harmful, pathogens refer specifically to those that can cause disease or other harm.

Pronunciation: PATH-a-jin
Also Known As: infectious agent, infectious microbe, germ, bug

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