经典美文.doc

An AIDS Mystery Solved (1) About 15 years ago, a well-meaning man donated blood to the Red Cross in Sydney, Australia, not knowing he has been exposed to HIV-1, the virus that causes AIDS. Much later, public-health officials learned that some of the people who got transfusions ? containing his blood had e infected with the same virus; presumably they were almost sure to die. But as six years stretched to 10, then to 14, the anxiety of health officials gave way to astonishment. Although two of the recipients have died from other causes, not one of the seven people known to have received transfusions of the man ’s contaminated blood e down with AIDS. More telling still, the donor, a sexually active homosexual, is also healthy. In fact his immune system remains as robust as if he had never tangled with HIV at all. What could explain such unexpected good fortune? (2) A team of Australian scientists has finally solved the mystery. The virus that the donor contracted and then passed on, the team reported last week in the journal Science. contains flaws in its ic script that appear to have rendered it innocuous ?.“ Not only have the recipients and the donor not progressed to disease for 15 years, ” marvels molecular biologist Nicholas Deacon of Australia ’s Macfarlane Centre for Medical Re-search, “ but the prediction is that they never will. ” Deacon speculates that this “ impotent