| The American Heritage® Book of English Usage. |
A Practical and Authoritative Guide to Contemporary English. 1996.
|
4. Science Terms: Distinctions, Restrictions, and Confusions
|
| § 20. contagious / infectious |
| Contagious refers to a disease that can be transmitted from one living being to another through direct contact (as with measles or AIDS) or indirect contact (as with cholera or typhus). The agent responsible for the contagious character of a disease is described as being infectious, the usual culprits being microorganisms such as viruses and bacteria or macroorganisms such as fungi or parasitic worms. Although an understanding of infectious agents didn’t fully develop until the late 19th century, the notion of being contagious, or bringing about (disease) through physical contact, has a rich history. From the time of Hippocrates, disease was believed to be caused by miasmas, which were alterations of the atmosphere that arose from the earth and attacked the body. To the ancients, the miasmatic theory of contagion conveniently explained widespread diseases such as plague or smallpox. The scores of individuals who came in contact with these changes were inflicted with disease. Acceptance in the late 1800s of the germ theory of disease transmission—and its description of the role of infectious agents—laid the miasma line of thought to rest. | 1 |
|
|
|
| The American Heritage® Book of English Usage. Copyright © 1996 by Houghton Mifflin Company. All rights reserved. |
|
|
