Some viruses, known as oncoviruses, contribute to certain forms of cancer.

It is notable as the first virus known to be defensive.

The first virus known to hit personal computers was called the Brain.

These were the most deadly viruses known to man.

This makes cowpox one of the most complicated viruses known.

He said the virus, known as Boza, was "not particularly well written."

The virus now known to cause fifth disease was not discovered until 1975.

Nor is, any organism other than this virus known which can do so,.

There are currently 21 families of viruses known to cause disease in humans.

Ebola is one of the most lethal viruses known to medical science.