New H.I.V. cases and AIDS deaths are both going steadily down in British Columbia, according to data released last week.
"We're particularly pleased to see that our treatment-as-prevention strategy has taken off big-time," said Dr. Julio S. G. Montaner, director of the British Columbia Center for Excellence in H.I.V./AIDS. His center was a pioneer in the strategy, which involves searching aggressively for people at risk of H.I.V. infection, talking them into being tested and putting those who are infected on antiretroviral drugs immediately, which lowers by 96 percent the chances that they will infect others.
In Vancouver, where he works, AIDS is concentrated in two largely separate groups: gay men and drug addicts. To reach the addicts, the city opened a center where they can inject under a nurse's supervision without fear of arrest; the nurses also offer medical care, including tests.
Testing is increasing, and syphilis rates are holding steady, Dr. Montaner said, so the drop in new cases is not a result of fewer tests or greater condom use.
AIDS cases remain steady in Canada's other provinces, except for those in the Prairies region, where they tripled, mostly among Indian addicts in Saskatchewan, which has no safe-injection center.
Last week, Science magazine named the treatment-as-prevention strategy, with the clinical trial of 1,763 couples on four continents that proved it worked, as its 2011 "Breakthrough of the Year."
Dr. Montaner said he is frustrated that rich countries will not donate enough money to roll out the strategy in poor countries with huge H.I.V. epidemics.