"Good afternoon. This is a disease specialist at the department of public health. Can you talk privately? The reason I'm calling is because one of your previous sexual partners has a sexually transmitted disease. Would you mind & coming in to undergo a few tests to see if you've been exposed?"
"What type of tests? What kind of sexually transmitted disease?"
"One of your previous sexual partners has AIDS."
It is a chilling phone call, still rarely made but likely to become more common as the disease spreads and more and more public-health authorities begin tracing the sexual intimates of AIDS...