SOCIETY owes a big debt of sympathy and admiration to the former disc-jockey, J.J. Chan, for his courageous decision to disclose his battle with AIDS. As the first local Chinese to talk openly about his disease, his example will be a powerful antidote to the prevalent and dangerous misconception that AIDS is an affliction of foreigners. Although the late Mike Sinclair did a great deal to promote awareness of the disease by devoting his last months to public education, it was all too easy for local people to view his case with complacency. Mr Chan's bravery will be harder for anyone to ignore. Despite the massive publicity campaign to encourage the practice of safe sex over the past few years, AIDS remains a great under-rated health-threat. Its spread in Asia has been dramatic, and the cultural acceptance of prostitution in many parts of the region, combined with widespread ignorance and complacency, has ensured its transmission in Hong Kong and China. As it happens, both Mr Sinclair and Mr Chan have been homosexuals. But it is now many months since the number of registered heterosexual sufferers from the HIV virus (which can lead to full-blown AIDS) overtook the number of homosexual sufferers here - just as it has elsewhere in the world. AIDS does not discriminate between races or between heterosexuals and homosexuals. Unprotected sex and promiscuity are high-risk behaviour between men and women, as well as between men. That is the message which still has to be understood. Newspapers have begun to carry stories of women infected by their husbands or boyfriends after an encounter with a prostitute. But these tragedies have tended to be anonymous and easy to forget. Mr Chan's courage will not be. It may also provide an encouragement to others to come forward too. The sooner other AIDS sufferers go public, the sooner the community can look forward to changes in the way people behave in private, too.