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Current Trends Continuing Increase in Infectious Syphilis -- United States

Through the first 46 weeks of 1987, 31,323 cases of infectious (primary and secondary) syphilis were reported to CDC through the MMWR Morbidity Surveillance System. This total exceeds the number of cases reported for the same period in 1986 by 32%. The projected annual incidence of infectious syphilis for 1987 is 14.7/100,000, which would be the highest rate since 1950. While 56% of all cases and 83% of the increase were reported from Florida, New York City (NYC), and California, 25 of the other 49 reporting areas also had increases. Nine areas had absolute increases of over 100 cases; in two of these areas, the relative increases were over 100% (Table 1). With the exception of Oregon and Connecticut, areas with high incidence rates experienced the greatest increases. Texas, with a 22% decrease in reported cases, and Louisiana, with a 9% decrease, were notable exceptions to the overall pattern of increase.

Fourteen areas reporting increases and five reporting decreases during the first 8 months of 1987 were asked to provide data on patients' race, sex, and sexual preference for further analysis. Overall, the areas providing this supplementary information contain 51% of the U.S. population and 79% of the syphilis cases reported through the first 46 weeks of 1987.

In the 14 areas reporting increases (13 states and NYC), relative increases were greatest for females and heterosexual males of all racial/ethnic backgrounds (Table 2). The greatest absolute increases occurred among blacks. The increase for males occurred among heterosexual males, and the decrease among homosexual/ bisexual males occurred primarily among white males (1). Exceptions to this overall pattern occurred in Connecticut and Georgia. In Connecticut, the relative and absolute increases were greatest among white heterosexual males. In Georgia, increases occurred only among white and black males, and a substantial portion of the increase appeared to be among homosexual/bisexual males.

In the five states reporting decreases, the only exception to the overall pattern of decrease occurred among white females. The number of reported cases increased by 51% (20 cases) in this group.

The pattern of increase differed among reporting areas. In some areas, such as Philadelphia and Los Angeles, the increase appears to have plateaued in the middle of 1987. However, in other areas, such as NYC, Florida, and Oregon, the increase continued to climb. In still others, such as Pennsylvania (excluding Philadelphia), the increase began during this period. Reported by: RG Sharrar, MD, M Goldberg, Philadelphia Dept of Public Health. Participating City and State Health Depts and STD Control Programs. Div of Sexually Transmitted Diseases, Center for Prevention Svcs, CDC.

Editorial Note

Editorial note: hese increases in infectious syphilis not only reverse the downward trend of the past 4 years, they also suggest an important shift in the epidemiology of the disease in the United States. As infectious syphilis has decreased among homosexual and bisexual males, largely because of changes in sexual behavior due to AIDS, a sizeable increase has occurred among heterosexuals. A similar shift was documented earlier in two small outbreaks (2,3).

While the cause of this increase is unknown, several hypotheses have been proposed. First, anecdotal reports from persons interviewing syphilis patients and their sexual partners indicate that prostitution in which nonintravenous drugs (especially "crack" cocaine) are exchanged for sex may be partially responsible for outbreaks of syphilis as well as other sexually transmitted diseases. A review of records of interviews in Philadelphia showed that the proportion of patients associated with both prostitution and drug use increased significantly between 1985 and 1987 (4).

Second, some investigators have suggested that routine use of spectinomycin (which does not appear to cure incubating syphilis (5,6)) in areas where a sizeable proportion of gonorrhea infections are caused by |gb-lactamase-producing organisms may explain the increase in infectious syphilis.* Events in NYC, Florida, and Los Angeles are compatible with this theory; however, for several other areas** with sizeable increases in reported syphilis, spectinomycin was not in common use before the increases began. While this mechanism may play a role in some areas, it alone cannot account for the nationwide increase.

Third, a decrease in the resources available for syphilis control programs has been suggested as a contributing factor. Twenty reporting areas** with sizeable increases in reported syphilis, spectinomycin was not in common use before the increases began. While this mechanism may play a role in some areas, it alone cannot account for the nationwide increase.

Third, a decrease in the resources available for syphilis control programs has been suggested as a contributing factor. Twenty reporting areas provided data on the number of staff available for syphilis control during 1985 and 1986. Ten of these areas reported increases in the number of persons interviewing patients with early syphilis between 1985 and 1986; four reported no change; and six reported decreases. Areas reporting increases in total syphilis morbidity were somewhat more likely to report a decrease in the number of interviewers; however, the association was not statistically significant.

The increases in infectious syphilis among females and heterosexuals are disturbing for three reasons. First, an increase in the number of females with syphilis will likely be followed by increased morbidity and mortality from congenital syphilis. Second, the marked increase among inner-city, heterosexual minority groups suggests that high-risk sexual activity is increasing in these groups despite the risk of HIV infection, which is already elevated because of the high prevalence of intravenous drug abuse. Third, studies in Africa and in the United States suggest that genital ulcer diseases such as primary syphilis increase the risk of HIV transmission (8,9).


  1. Landrum S, Beck-Sague C, Kraus S. Racial trends in syphilis among men with same-sex partners in Atlanta, Georgia. Am J Public Health 1988;78:66-7.

  2. Centers for Disease Control. Early syphilis--Broward County, Florida. MMWR 1987;36:221-3.

  3. Lee CB, Brunham RC, Sherman E, Harding GKM. Epidemiology of an outbreak of infectious syphilis in Manitoba. Am J Epidemiol 1987;125:277-83.

  4. Rolfs RT, Goldberg M, Sharrar RG. Outbreak of early syphilis in Philadelphia. Presented at the 115th annual meeting of the American Public Health Association and related organizations, New Orleans, Louisiana, October 18-22, 1987.

  5. Petzoldt D. Effect of spectinomycin on T. pallidum in incubating experimental syphilis. Br J Vener Dis 1975;51:305-6.

  6. Rein MF. Biopharmacology of syphilotherapy. J Am Vener Dis Assoc 1976;3:109-27.

  7. Schroeter AL, Turner RH, Lucas JB, Brown WJ. Therapy for incubating syphilis: effectiveness of gonorrhea treatment. JAMA 1971;218:711-3.

  8. Quinn TC, Glasser D, Matuszak DL, et al. Screening for human immunodeficiency virus (HIV) infection in patients attending sexually transmitted diseases clinics: risk factors and correlates of infection. Presented at the International Society for STD Research, Atlanta, Georgia, August 2-5, 1987.

  9. Cameron DW, Plummer FA, Simonsen JN, et al. Female to male heterosexual transmission of HIV infection in Nairobi. Presented at the International Society for STD Research, Atlanta, Georgia, August 2-5, 1987. *Parenteral penicillin regimens used to treat gonorrhea have been shown to cure incubating syphilis acquired at the same time as gonorrhea infection (7). **Arizona, Baltimore, Connecticut, North Carolina, Oregon, and Philadelphia.

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