Report on a New Form of H.I.V. Brings Alarm, Not Surprise
New York City health officials make first public report of rare and potentially more aggressive new strain of HIV; experts worry that combination of resistance to nearly all anti-retroviral drugs and swift progression to full-fledged AIDS could signal new, more menacing kind of infection; officials have long warned that people have developed false sense that AIDS no longer poses significant threat since development of anti-retroviral drugs in 1990's; scientists say that more testing is necessary to be certain about extent of threat; photos (M)
