Inclusion Criteria

Risk Behavior:

PART B ONLY:

• HIV-infected partner (primary partner) must have a known risk factor for HIV infection, such as
• Bisexual male.
• IV drug user.
• Hemophiliac male.
• Recipient of HIV-contaminated transfusion.

Participants must meet the following criteria:

• Heterosexual couples in which at least one member is HIV-infected. Comparison group consists of heterosexual couples concordant that are both HIV infected.
• Able to speak English or Spanish.

PART A secondary partners:

• Risk factor for HIV infection other than heterosexual contact, such as
• Evidence of any past or present parenteral drug use by self report, physical examination, or urine test.
• History of homosexual activity (if male) within 5 years prior to study entry.

PART B secondary partners:

• Risk factor for HIV infection other than sexual contact with the primary partner, such as
• Evidence of any past or present parenteral drug use by self-report or by urine test.
• History of homosexual activity (if male) at any time since 1978.
• Sexual contact with another person with an HIV risk factor at any time since 1978, unless secondary partner is documented to be HIV uninfected subsequent to the last contact with such person.