Which Word Wednesday: Contagious vs. Infectious

By January 30, 2013 language No Comments

Top-10-Infectious-Contagious-Diseases-345x272Winter cold and flu season is upon us. (Run for your lives!) Reports from the news and from my friends and family who have suffered say this year’s strain is a doozie. It’s not gotten me yet, but I’ve contracted some sort of head cold instead. (Annoying, yes, but better than the flu.)

When illness rises up all around us, the fear goes with it, prompting us to ask questions like: Is it contagious? Is it infectious? How much hand sanitizer do we need to keep the germs away? If we all stay sequestered till May, will that help?

I don’t have the answers to these very pressing questions. But today’s Which Word Wednesday can answer the distinction between what is contagious and what is infectious. Let’s look at the definitions from The Oxford American Dictionary:

contagious :: adjective
(of a disease) spread from one person or organism to another by direct or indirect contact

infectious :: adjective
(of a disease or disease-causing organism) likely to be transmitted to people, organisms, etc., through the environment

That’s pretty straight forward! You need contact to be contagious—keep the Cs together. Infectious transmittal is environmental—keep the vowels together.

Mark Davidson gives additional insight in Right, Wrong, and Risky: A Dictionary of Today’s American English Usage:

Any disease you catch—from food, water, air, or human or animal contact—is infectious. . . . The word contagious, derived from a Latin term for “in touch with,” describes only those infectious diseases that are communicated by contact.1

So all diseases are infectious but only some are contagious. Good to know.

What’s my WWW verdict? Whether infectious or contagious, being sick is no fun. Stay healthy out there!

What’s your verdict? Do you know the difference between a contagious disease and an infectious disease? Have you been bathing in anti-bacterial gel? Do share in the comments.


Check out previous Which Word Wednesday verdicts here.
1. Mark Davidson, Right, Wrong, and Risky: A Dictionary of Today’s American English Usage (New York, NY: W. W. Norton & Company, 2006), 172.

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