When conceptual artist Diamanda Galas recently performed her "Plague Mass" in Italy (the work that will be the centerpiece of her rare appearance Wednesday night at the Vic Theatre on Chamber Music Chicago's DejAvant Series), suddenly the same Italian officials who had been so quick to call pop singer Madonna blasphemous were struggling for new adjectives to describe the far more extreme style of Galas.

As one editorial put it, Galas recalled, "After the fake scandal and fake blasphemy of Madonna, now we have a real blasphemer."

"That's not an unusual reaction," says Galas, a New Yorker, who added that the many double meanings and the use of satire and metaphor in her work have often led to misunderstandings on the part of those who want to see it on only a monochromatic level. "My records have been taken to priests for exorcism."

Galas' 1981 debut album, "The Litanies of Satan," for instance, became and underground cult classic among heavy metal fans who interpreted her spine-chilling use of solo voice, tape and electronics to re-create "the emeraldine perversity of the live struggle in Hell" as a literal exercise, when in actuality the work was a setting of the poem of the same name by 19th Century French poet Charles Baudelaire.

Gothic music perhaps?

Galas rejects the term as archaic and irrelevant. "If 'Gothic' means 'The Fall of the House of Usher,' fine," she said. "If it means a bunch of kids dressed in black leather shooting speed, I'm not interested. When I was in Berlin, a bunch of girls came up to me and said, 'Oh, we can't wait for your next album. We perform our satanic rituals to your songs all the time.'… My music isn't for bored teenagers."

But if Galas is a misfit in the rock world, she is equally a misfit in the world of new music and the avant-garde. An established pianist and operatically trained bel canto singer with an extraordinary range that extends from contralto to coloratura (often in a single bound), Galas uses her unique voice to express an infinite variety of vocal textures and timbres.

Galas has drawn on all her unusual resources (including dramatic costuming and gestures) for her constantly evolving "Plague Mass," which she began in 1984. The work was written in response to the AIDS epidemic, and to date three albums have been released, which form the "Masque of the Red Death" trilogy. The full work comprises "Divine Punishment," "Saint of the Pit," and "You Must Be Certain of the Devil," all of which are being re-released later this year on a double compact disc set by Mute Records. A live recording of the work, featuring much new material, is due this week.

"I have vowed to keep performing the work until the end of this epidemic," said Galas, who has lost a brother and "more friends than I can count" to AIDS. "It's extreme music to represent an extreme situation. One could say it's the intravenal sound of the epidemic rather than an outside look at it---the nightmare of the experience itself."

Galas says that if it weren't for the prejudice and indifference associated with AIDS, she would have taken a slightly different tack with the work.

"If AIDS were considered as, say, cancer is nowadays, then I would be doing a requiem mass, not a plague mass. 'Plague' refers specifically to a quarantine mentality as represented in Leviticus, by the way in which a disease is received within the community, the way people with it are isolated as 'unclean,' much as lepers used to be.

"We're dealing with an epidemic that attempts to isolate people, to cut them off from others…

"A requiem mass helps to pacify the living, so they can feel that the dead are resting in peace. As far as the dead from this disease, I don't think of them as resting in peace. When I have dreams about my brother, he is always angry. I haven't had a single peaceful dream of him in four years."

Yet as horrifying as many moments of the "Plague Mass" are, there are humorous and hopeful moments as well. In particular, the work's finale is a frenzied Gospel sendup that satirizes the hypocrisy of many religious and civil leaders concerning AIDS.

"Some people have called the work 'music of the dying,' which I reject. It's important to give people hope. When I use the Scriptures (in the work), I use texts such as Psalm 88, which is not so much a statement of 'blame,' but despair. But the point is that even in despair, you're still reaching out.

"Whether a person believes in God or not--even if it's a God invented by despair—it's still a reaching up—or down, depending on your point of view—for comfort."