the common cold http://en.wikipedia.org/wiki/Common cold also known as nasopharyngitis, acute viral rhinopharyngitis, acute coryza a viral infectious disease of the upper respiratory system, caused primarily by rhinoviruses and caronaviruses. Common symptoms include a cough, sore throat, sinus aches and fever. There is currently no known treatment that shortens the duration; however, symptoms usually resolve spontaneously in 7 to 10 days, with some symptoms possibly lasting for up to three weeks *
influenza virions, magnified approximately 100,000 times
the newest devil http://en.wikipedia.org/wiki/Computer_virus
is a computer program that can copy itself and infect a computer.
The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware andspyware programs that do not have the reproductive ability.
A true virus can spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disc,CD, DVD or USB drive. *