The World Health Organization (WHO) says as many as 10 (36) _______persons worldwide may have the virus (病毒) that (37) _______ AIDS. Experts believe about 350-thousand persons have the (38) _________. And one million more may get it in the next five years. In the US, about 50,000 persons have died with AIDS. The country’’s top (39) _______ official says more than 90 percent of all Americans who had the AIDS virus five years ago are dead.
There is no (40) _________ for AIDS and no vaccine (疫苗) medicine to prevent it. However, researchers know much more about AIDS than they did just a few years ago. We now know that AIDS is caused by a virus. The virus invades healthy cells, including white blood cells that are part of our (41) ________ system against disease. It takes control of the healthy cell’’s genetic material and forces the cell to make a copy of the virus. The cell then dies. And the viral particles move on to (42) ________ and kill more healthy cells.
The AIDS virus is (43) _______ in a person’’s body fluids. (44) __________________________. It also can be passed in blood products or from a pregnant (怀孕) woman with AIDS to her developing baby.
Many stories about the spread of AIDS are false. (45) __________________________. You can’’t get it by touching drinking glasses or other objects used by such persons. (46) __________________________.