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Infectious Diseases




what causes them and are they contagious?


Parasites are germs or microbes that live off, or at the expense, of someone else (i.e., other microbes, plants, animals, or humans.) There are many types of parasites, ranging from dangerous microbes (e.g., malaria parasites) to relatively harmless but irritating parasites (e.g., pinworm). Some parasites have simple life cycles with only one host while other parasites have complex parasites complex life cycles with many hosts. The malaria parasite is transmitted to humans by the bite of a mosquito, whereas the pinworm parasite can be transmitted from one human to another. There a many types of parasites in nature.

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Response by:

Peter D Walzer, MD Peter D Walzer, MD
Professor of Clinical Medicine
College of Medicine
University of Cincinnati