How and when the virus first entered the United States is not known.

And that was so especially in 1979 because the virus had just entered the community.

The virus usually enters the body through the nose or throat.

The virus enters the central nervous system in about 3% of infections.

In what ways can the virus enter the body and become entrenched?

The critical events, they decided, take place in the first days or weeks after the virus enters the body.

The virus then enters the blood stream on the second or third day.

Now it seems that the virus can enter the human body in various other ways.

The newspaper's technicians said they were not sure how the virus had entered the computer system.

Others get sores near the area where the virus has entered the body.