The full scale of the epidemic - and that the virus had been silently emerging over several decades - was not known.

When a new virus emerges, the antivirus experts take a sample back to their laboratories.

That's why new viruses are now emerging at a faster rate.

A virus could emerge, evolve, and move between species.

The next wave in biology, the desired end result of analyzing how viruses emerge, will be characterized by the scientists fighting back.

Overseas, viruses are emerging as a tool for political terrorism.

After infection the virus lies dormant in the body but can emerge later to cause shingles.

This indicates that viruses emerged early in the evolution of life and existed before modern cells.

So far 19 people have died, 23 have been contaminated and the virus has emerged in ten Asian countries.

Two years after the virus first emerged in Asia, cases among humans are on the rise.