The virus had entered their bloodstreams and multiplied in their cells.

Other viruses survive, multiply and become more common.

The virus infects and multiplies in cancer cells but does not attack normal cells.

Over the course of a week the virus multiplied very rapidly, exploding cell after cell in their bodies.

If a person's immune system is not working properly, the virus can multiply explosively and cause a severe infection.

Surely by now the virus had lodged within her and was multiplying.

But even though no symptoms are present, the virus is multiplying (or making copies of itself) in the body during this time.

The specialist will order blood tests to check your liver enzyme levels and to see whether the virus is still multiplying.

Occasionally, the viruses will multiply or move from one area of the body to another, and that is when herpetic disease breaks out.

Interferons work best for people who have high levels of liver enzymes and in whom the virus is multiplying.