One of our library computers contracted a virus once.  Apparently this was
a computer set up in the public area so it would be accessible both to library
staff and to users....for example, if your bibliography was on disk and you
wanted to check something against the card catalog.   Someone came in and used
a disk, possibly copied a file to the hard drive, etc....anyway it became
'infected.'   It is actually possible that many of our computers have some
type of "virus" on them, since I believe some are benign.
 
Dean DeBolt