HIV disrupts this process by directly infecting the helper T-cells.

HIV directly infects a small number of T helper cells, and also impairs other immune system responses indirectly.

It may be used to directly infect the patient with NDV or to make cancer vaccines.

During this time, he directly infects 38 people.

One new finding is that macrophages may directly infect rectal cells and cervical cells.

And then there is the dreaded Boza virus, which an alarmed reader informed me is "the first virus that directly infects the 32-bit protected memory Windows environment."

He and others also hope to find less invasive ways of delivering new genes to liver tissue, perhaps packaging them into carrier bubbles of fat, or into cold viruses that can directly infect liver cells.

Pigs have been termed the mixing vessel of flu because they can be infected both by avian flu viruses, which rarely directly infect people, and by human viruses.

One study has suggested that the virus may be able to directly infect cells in the colon.