Most Americans believe they know what causes AIDS. For a decade, scientists, government officials, physicians, journalists, public-service ads, TV shows, and movies have told them that AIDS is caused by a retrovirus called HIV. This virus supposedly infects and kills the "T-cells" of the immune system, leading to an inevitably fatal immune deficiency after an asymptomatic period that averages 10 years or so. Most Americans do not know--because there has been a virtual media blackout on ...