The Parvoviridae family includes the smallest known viruses, and some of the most environmentally resistant.

There are hundreds of thousands of known viruses, and potentially millions not yet described.

It is sufficiently unrelated to any other known virus that it may belong to a new family.

The Internet computer system can have conventional antivirus software to detect known viruses.

This virus has a number of unique features that were unlike any other known virus when it was described.

In 1993 only about 10 percent of known viruses were considered destructive, harming files and hard drives.

And, incidentally, only a small minority of the known viruses the authors found actually infect humans.

You mentioned earlier Doctor, that there were over 5000 known viruses.

The agent is smaller by far than any known virus, resistant to extreme heat and invisible to the body's immune system.

And there is no known virus that causes disease in every infected individual.