11.   But because the virus can infect genital areas not covered by condoms, they afford incomplete protection.

12.   But somehow the virus had infected them and embedded itself in their tumors.

13.   But the virus infected only cells that were dividing.

14.   But there is mounting evidence that the virus infects humans and is associated with certain types of human tumors.

15.   By all accounts, the AIDS virus infects and kills T cells.

16.   Clear mucous is produced when the cold virus first infects our nose and sinuses.

17.   Gene therapy works by inserting desired genes into harmless viruses, then allowing the viruses to infect and spread the genes in patients.

18.   His recent work at Harvard has focused on advancing understanding of how viruses infect human cells and how those cells respond.

19.   Kim said the flu virus infected cells in its host, reproduced inside these cells and then broke out to spread the infection to other cells.

20.   Macro viruses infect a computer in a manner similar to the way a retrovirus, such as the herpes virus, infects the human body.