persons in North America, Western Europe, Australia, and New Zealand were living with HIV/AIDS (UNAIDS and World Health Organization, 1996) Among all AIDS cases reported to the World Health Organization (WHO) by 1993, more than one-half came from the United States and Europe (40% and 13%, respectively) (Way and Stanecki, 1994). However, because reports from the developing world are less complete than those from the developed world, WHO estimates that cases reported by the United States actually represent less than one-sixth of the world total of AIDS cases (World Health Organization, 1995a).
Overall, in most developed countries, the incidence of classical RTIs such as gonorrhea and syphilis declined rapidly during the 1980s among middle and upper socioeconomic strata; in North America, however, the incidence of these same RTIs remained stable or actually increased within young, low-income, minority populations. HIV infection has also become entrenched in these same disenfranchised groups, and the proportion that is spread through heterosexual behaviors is increasing.
The epidemiology of RTIs in developing countries differs greatly from that in developed countries (Wasserheit, 1989; Brunham and Embree, 1992; Over and Piot, 1993; Piot and Islam, 1994; World Health Organization, 1995b). Overall, RTIs are a more frequent health problem in developing countries. WHO estimates at least 333 million new cases of curable STDs occurred globally in 1995 (World Health Organization, 1995b), mostly in developing countries. RTIs are among the top five causes of consultation at health services in Cameroon, representative of many African countries; and among adults, RTI is the leading diagnosis (Meheus, Schulz, and Cates, 1990). In Zimbabwe, up to 10 percent of the population had a documentable RTI (Laga, 1994). Intensive studies of women in India, Bangladesh, and Egypt have found RTI rates ranging from 52 percent to 92 percent, less than one-half of which were recognized by the women as abnormal (Bang et al., 1989; Wasserheit et al., 1989; Younis et al., 1993; Singh et al., 1995). Among RTI syndromes, the etiology of genital ulcer infection differs significantly from that in the developed world: syphilis and chancroid are the major causes of genital ulcers in tropical countries, with genital herpes accounting for a smaller proportion (Brunham and Ronald, 1991). Table 3-2 shows the prevalence of RTIs among pregnant women in some developing countries for which there are data.
Syphilis in developing countries remains at levels that were seen in developed countries a century ago. One must be cautious in looking at the data, however, because a seropositive serological test for syphilis