The news article "AIDS tax" mooted for S.Africa as epidemic bites reports that roughly 11 percent of South Africa's 45 million people are infected with the AIDS virus. I'd heard that AIDS is a huge problem in Africa, so that statistic didn't surprise me. What did was "Sixty-six percent of those surveyed felt they were not at risk of infection -- including 51 percent of those who later turned out to be HIV-positive."

What's the explanation for that 51% being so wrong? Do they have accurate information about HIV transmission? Are they mistaken in the belief their sexual partner is monogamous and/or HIV-negative? Are they simply in denial? I'm baffled.