Syphilis in the United States: 1967-1979.
Reported data on cases of primary and secondary syphilis in the United States during 1967-1979 were analyzed by age, race, sex, and reporting source. Although the incidence of primary and secondary syphilis fluctuated little in the United States between 1967 and 1979, the ratio of male to female cases increased twofold, from 1.5:1 to 3:1. Cases in men, primarily those aged 25-39 years, reported by public clinics increased from 32% to 56% of the total cases reported; in particular, cases among white males reported by public clinics increased by 351%. The percentage of white men with early syphilis who attended public clinics and who reported at least one male sex partner increased from 38% in 1969 to 70% in 1979. These findings suggest that an essential change occurred in the epidemiology of early syphilis in the United States: white gay men became proportionately more burdened by the disease, and increasing transmission of the disease occurred within this segment of the population in the United States.