Communicable Diseases

Epidemiology

Communicable diseases, sometimes called infectious diseases, are illnesses caused by organisms such as bacteria, viruses, fungi and parasites. Sometimes the illness is not due to the organism itself, but rather a toxin that the organism produces after it has been introduced into a human host.

Communicable diseases may be transmitted (spread) by:

• one infected person to another, or

• from an animal to a human, or

• from some inanimate object (doorknobs, table tops, etc.) to an individual. 

Some communicable diseases can be spread in more than one way.

To learn more about communicable diseases, select anyone of the links that follow:

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Last Revised: December 06, 2011