According to Wikipedia, a virus is a sub-microscopic infectious agent (sounds familiar?) that is unable to grow or reproduce outside a host cell. Therefore, the more you entertain and feed them, the more YOU get harassed.
Although viruses cause disruption of healthy homeostasis, resulting in disease, they may exist relatively harmlessly within an organism. meaning,if you do not show fear
Often, a virus is completely eliminated by the immune system. (remember Rule No. 5?)