Origin of contagious
Can be confusedcontagious infectious (see synonym study at the current entry)
Examples from the Web for contagious
Many doomsday preppers have spent their lives stocking up for an emergency of the type this contagious hemorrhagic fever presents.
First: Was he contagious when boarding the plane and are his plane-mates therefore at risk?
While the virus can remain incubated for up to 21 days, it is not contagious until a patient begins showing symptoms.CDC Director: First U.S. Ebola Patient ‘Critically Ill’|Abby Haglage|September 30, 2014|DAILY BEAST
The resultant pop culture is as morbid and contagious as the epidemics they depict.Ebola Rages in West Africa, Reigniting Humanity’s Oldest Fear: The Plague|Scott Bixby|August 4, 2014|DAILY BEAST
But the most important thing to note, says Monroe, is that only those who are symptomatic are contagious.
The members of the vestry could not be supposed to escape the contagious excitement inseparable from the occasion.Sketches by Boz|Charles Dickens
There were autumnal fevers too, and a contagious and destructive throat-distemper,—diseases unwritten in medical hooks.Old News|Nathaniel Hawthorne
That contagious misery spoiled one's joy, freedom, and courage.Egotism in German Philosophy|George Santayana
This morning I wandered about where the different companies were target-shooting, and their glee was contagious.
A contagious fever raged among the prisoners, and of this the venerable abb was aware.Old and New Paris, v. 2|Henry Sutherland Edwards
British Dictionary definitions for contagious
Derived Formscontagiously, adverbcontagiousness, noun
Medicine definitions for contagious
Related formscon•ta′gious•ness n.
Science definitions for contagious
A contagious disease is one that can be transmitted from one living being to another through direct or indirect contact. Thus the flu, which can be transmitted by coughing, and cholera, which is often acquired by drinking contaminated water, are contagious diseases. Although infectious is also used to refer to such diseases, it has a slightly different meaning in that it refers to diseases caused by infectious agents-agents such as viruses and bacteria that are not normally present in the body and can cause an infection. While the notion of contagiousness goes back to ancient times, the idea of infectious diseases is more modern, coming from the germ theory of disease, which was not proposed until the later nineteenth century. Contagious and infectious are also used to refer to people who have communicable diseases at a stage at which transmission to others is likely.