In which circumstances would it be justifiable for one to disclose an individual's HIV/AIDS status in South Africa?The answer should be from a legal, moral and religious perspective.
Someone else's status, or one's own? If one's own, anytime you even think about getting sexually involved with anyone. Even if you use a condom, it's just not ok morally to not tell your partner, in South Africa or anywhere else in the world.
As far as the law goes, my understanding is that there is (or very soon will be) a disclosure law in SA, meaning that one legally must disclose their status (if HIV positive) to potential partners. There are those who claim this is not likely to work, given the nature of people, and that counseling and education would be better. On the other hand, it's not like you can just look at someone in the early stages and tell.
Someone else's status is a different thing. I feel that usually people should mind their own business, but if you know someone is HIV positive and you know they are involved with someone else, that other person really needs to know. Legally, you probably can't tell them for someone else, but morally they should know. This could be a criminal act, to break confidentiality. This may be "sticking your nose where it's not wanted." But morally, that person needs to know.
In terms of religion, that's hard to say. It might depend on what religion we're talking about. Religion is a sticky subject and is best left to your own individual sense of whatever your religion might teach. Religion, as a whole, seems a subject best left alone except inside your own heart. If your religion is truth to you, your moral sense will tell you what to do, anyway.