File viruses, such as Jerusalem, are sometimes called parasitic viruses.

They are often called spyware or viruses, but they are not any of these.

Because many of these viruses take a long time to produce symptoms, they are often called slow viruses.

Viruses of the lytic cycle are called virulent viruses.

In the late part of the 1800s Martinus Beijerinck showed that there were small particles called viruses.

Protozoa, bacteria, and the self-reproducing proteins that some people call viruses.

Then there are the legitimate programs that have been infected with subprograms called viruses .

The very smallest germs are called viruses.

TOM: Now, were you calling them "viruses" by that point?

Other viruses, called neurotropic viruses, move along nerves to places the immune system cannot reach.