Noah Webster
Contagion
CONTAGION, noun [Latin , to touch.]
1. Literally, a touch or touching. Hence, the communication of a disease by contact, or the matter communicated. More generally, that subtil matter which proceeds from a diseased person or body, and communicates the disease to another person; as in cases of small pox, measles, anginas, and malignant fevers; diseases which are communicated without contact. This contagion proceeds from the breath of the diseased, from the perspiration of other excretions.
2. That which communicates evil from one to another; infection; that which propagates mischief; as the contagion of vice or of evil examples.
3. Pestilence; a pestilential disease; venomous exhalations.