Definitions of contagion on the Web:

• contagious disease: any disease easily transmitted by contact
• infection: an incident in which an infectious disease is transmitted
• the communication of an attitude or emotional state among a number of people; "a contagion of mirth"; "the infection of his enthusiasm for poetry"
  wordnetweb.princeton.edu/perl/webwn

• Contagion is a medical thriller written by Dr. Robin Cook.
  en.wikipedia.org/wiki/Contagion_(novel)

• 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
  en.wiktionary.org/wiki/contagion

• contagious - easily diffused or spread as from one person to another; "a contagious grin"
• contagious - catching: (of disease) capable of being transmitted by infection
  wordnetweb.princeton.edu/perl/webwn

• Contagious is the 9th album by heavy metal band Y&T. It was their last of the 1980's.
  en.wikipedia.org/wiki/Contagious_(album)

• Contagious is the second demo album released by Christian rock band Third Day in 1994. Like their previous effort, Long Time Forgotten, it was ...
  en.wikipedia.org/wiki/Contagious_(Third_Day_album)

• Contagious - "Contagious" is a song by The Isley Brothers, featuring Ronald Isley in 2001. The song was written and produced by R. Kelly, who was also featured on the song alongside R&B singer Chanté Moore.
  en.wikipedia.org/wiki/Contagious_(song)

• Contagious is the second album by soul singer, Peggy Scott-Adams. It followed hot on the heels of the success of her debut album "Help Yourself. ...
  en.wikipedia.org/wiki/Contagious_(Peggy_Scott-Adams_album)

• contagious - Of a disease, easily transmitted to others; Of a fashion, laughter, etc., easily passed on to others; Of a person, having a disease that can be transmitted to another person by touch
  en.wiktionary.org/wiki/contagious

• The tendency of an economic crisis to spread from one market to another. In 1997, political instability in Indonesia caused high volatility in ...
  www.info-forex.com/glossary.htm

• contagious - transmitted by direct or indirect contact.
  www.womenshealthzone.net/glossary/c/

• The process by which one person infected with a disease passes it to another, either through direct skin contact, inhaled droplets or contact with ...
  www.rtnda.org/pages/media_items/bioterrorism-resources-online-glossary302.php