Study Objective: During 1987, the rate of syphilis among heterosexual adults in Oregon increased 159%, yet the number of cases of gonorrhea remained stable. Our study was done to evaluate why the same control measures contained gonorrhea but not syphilis in this population.
Design: Exploratory case-control study.
Setting: Public health clinics in Portland, and Salem, Oregon.
Patients: All 146 heterosexual adults with early syphilis and all 164 heterosexual adults with acute gonorrhea reported to the public health clinics during April to July 1988.
Intervention: A questionnaire was administered to all syphilis case-patients and control patients (those with gonorrhea) at the beginning of the routine, sexually transmitted disease (STD), investigative interview.
Measurements and Main Results: Syphilis case-patients had contact with an average of 5.0 sex partners for whom they could not supply locating information sufficient to initiate partner notification. In contrast, patients with gonorrhea had contact with an average of 0.4 sex partners for whom they could not supply locating information (P < 0.005). The 28% (41 of 146) of syphilis case-patients who reported having exchanged sex for drugs or money accounted for 72% (527 of 729) of the unlocatable partners exposed to syphilis. In contrast, the 17% (28 of 164) of patients with gonorrhea who reported having exchanged sex for drugs or money accounted for 36% (25 of 69) of the unlocatable partners exposed to gonorrhea.
Conclusions: Because patients infected with syphilis have relatively large numbers of anonymous sexual encounters, prevention strategies that supplement partner notification are urgently needed to control the syphilis epidemic among adults.