attributed to five STDs (i.e., chancroid, chlamydial infection, gonorrhea, HIV infection, and syphilis) in men was also high.

AIDS-associated deaths, which account for the largest number of STD-related deaths, have received considerable attention. Of 513,486 persons with AIDS reported in the United States through December 1995, more than 62 percent (319,849) have died (CDC, 1995b). As indicated above, many other STDs cause potentially fatal complications in adults as well as in the fetus or infant. The largest number of deaths related to STDs other than AIDS are caused by cervical and other human papillomavirus-related cancers; liver disease (e.g., chronic liver disease and liver cancer) caused by hepatitis B virus; pelvic inflammatory disease and ectopic pregnancy; and various pregnancy, fetal, and neonatal complications.

In a recent study completed by investigators at the CDC, more than 150,000 deaths were directly attributed to STDs, including AIDS, from 1973 through 1992 among American women 15 years of age and older (Ebrahim et al., 1995). According to this report, the three leading causes of STD-related deaths in 1992 among these women were cervical cancer (57 percent of deaths), AIDS (29 percent), and hepatitis B and C virus infection (10 percent), all of which are related to viral STDs (Figure 2-4). From 1972 through 1984, the annual number of these STD-related deaths declined by 24 percent; but from 1984 through 1992, STD-related deaths increased by 31 percent, largely as a result of AIDS-related deaths.

In developing countries, the impact of STDs on health also is very substantial. Even when deaths caused by human papillomavirus and hepatitis B virus were not considered, five other STDs (HIV infection, chlamydial infection, gonorrhea, syphilis, and chancroid) ranked among the top 20 causes of loss of productive life in a sub-Saharan African country (Over and Piot, 1993).

The evidence that "ulcerative" STDs, such as chancroid, syphilis, and genital herpes, and "inflammatory" STDs, such as gonorrhea, chlamydial, and trichomoniasis, increase the risk of HIV infection has developed incrementally over the past decade. Although the proportion of HIV infections that could be prevented in the United States by preventing other STDs has not yet been well defined, current estimates suggest that much—perhaps most—of the heterosexually transmitted HIV infection could be prevented by reducing other underlying STDs.

The earliest cross-sectional studies found an association between genital