Contagion
WordNet
noun
(1) The communication of an attitude or emotional state among a number of people
"A contagion of mirth"
"The infection of his enthusiasm for poetry"
(2) An incident in which an infectious disease is transmitted
(3) Any disease easily transmitted by contact
WiktionaryText
Noun
- A disease spread by contact
- The spread or transmission of such a disease
- The spread of anything harmful, as if it were such a disease