PARASITES. “Both computer and biological viruses, they explain in their paper, can be defined as “information that codes for parasitic behavior.” In biology, a virus’s code is written in DNA or RNA and is much smaller than the code making up a computer virus. The DNA of a flu virus, for example, could be described with about 23,000 bits, whereas the average computer virus would fall in a range 10 to 100 times bigger.”
http://blogs.scientificamerican.com/observations/could-human-and-computer-viruses-merge-leaving-both-realms-vulnerable/