Aral, Sevgi O. PhD, MSc, MA*; O'Leary, Ann PhD†; Baker, Charlene PhD‡
From the *Division of STD Prevention, the †Division of HIV/AIDS Prevention-IRS, and the ‡Division of Violence Prevention, National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, Atlanta, Georgia
The authors thank Emmet Swint, Patricia Jackson, and Melanie Ross for their outstanding support in the preparation of this article.
Correspondence: Sevgi O. Aral, PhD, MSc, MA, Division of STD Prevention, Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Mailstop E-02, Atlanta, GA 30333. E-mail: SAral@cdc.gov
The geographic patterning of the HIV epidemic, as it evolves in the United States, has been remarkable in many ways. In the past 15 years, there has been a growth in the proportion of AIDS cases in blacks, in residents of the southeastern region, and in men and women infected through heterosexual contact.1 Sexually transmitted diseases (STDs) other than HIV follow epidemiologic patterns similar to those of AIDS,2 and syphilis and gonorrhea, like HIV, also disproportionately affect blacks in the nonurban south.3 This special issue focuses on STDs and their determinants in the southern United States.
In-depth looks at the epidemiology of specific sexually transmitted infections globally (and in the United States) suggest certain insights. First, populations are composed of many diverse subpopulations, and each population-level trajectory of an epidemic consists of many distinct subpopulation trajectories.4,5 The trajectory of an epidemic of a specific STD differs in subpopulations depending on when and where the infection was introduced; the natural history and transmissibility of the infection; the structure of sexual networks; the demographic, economic, social, and epidemiologic contexts; and the state of the health system.6
Second, contextual factors such as demographic, economic, and social composition and trends are important determinants of epidemic trajectory. The important effects of context on the trajectory of an epidemic often influence sexual networks, the health system, or cofactor effects that directly modify transmission efficiency.7
Third, the temporal dimension plays an important role in STD epidemiology and prevention.8–11 STD epidemics evolve through sometimes predictable phases characterized by changing patterns in the distribution and transmission of STD-causing pathogens within and between subpopulations. Furthermore, STD-specific prevention and control programs also go through phases of development, implementation, scale-up, and maturation, and impact STD epidemiology.12,13
Fourth, the structures of sexual links in a population—sexual networks and their evolution through time—are an important determinant of the spread of STD in populations.6
It is within this framework that we approach the issue of high rates of HIV and STD prevalence in the southern United States. A review of 2 reportable sexually transmitted infections other than HIV suggests that (see Figs. 1 and 2): 1) regional differences in primary and secondary syphilis, which had been particularly marked among black men and women, have declined remarkably over the past decade. In fact, currently, the highest primary and secondary syphilis rates are observed in the West for white men; and 2) regional differences in gonorrhea rates have declined much less over the past decade. Regional differentials in gonorrhea rates are not marked among white men and women. Among black men and women, gonorrhea rates in the South have declined over the past decade, and the highest gonorrhea rates are reported in the Midwest.
One measure of heterogeneity of STD morbidity in subpopulations is the disparity ratio, which depicts the ratio of black STD rates to white American STD rates. For the 2 STDs we have reviewed, the disparity ratio is actually higher in other regions than in the South, indicating that gonorrhea and syphilis rates among blacks are closer to rates among whites in the South than they are in the Midwest and Northeast (Figs. 3 and 4).
Unlike the bacterial STD discussed here, viral STD cannot be cured (although they can be suppressed [herpes simplex virus]) and/or made less infectious [HIV]) through medication) and are more likely to persist in a particular geographic region. The HIV epidemic—whose emergence in the South may have been partly influenced by the high levels of bacterial STD, particularly syphilis, in the mid-1990s—is likely to endure and remain disproportionately concentrated in the southern United States.
This special issue focuses on STD in the southern United States and the societal determinants that influence STD rates. The articles in the issue address many topics that might be hypothesized to account for the differences in HIV/STD prevalence between the South and other regions of the country. There are remarkable sociodemographic differences between the southeastern United States and other parts of the country. The percentage of the population that is of African descent is considerably higher in the South than elsewhere. Blacks are disproportionately affected by STD, including HIV, independently of region of residence. Second, the deep South contains most of the most impoverished counties in the country.14 For example, of the 229 counties with the highest poverty rates (more than 25%) in the country, 78% are in the South. Moreover, more people residing in the South live in nonurban areas. Of 229 poorest counties, 94% are rural. Fully 92% of rural blacks live in the South. In the remainder of this article, we review the 3 areas of sociodemographic difference outlined here and discuss the evidence provided in the articles included in this issue for each.
Blacks and Sexually Transmitted Disease in the South
As pointed out by Farley,2 blacks experience high STD rates everywhere in the country, and their rates are not elevated in the South relative to the rest of the country. Thus, part of the disproportionate prevalence of STD in the South is related to the overrepresentation of blacks in this region.
This elevated prevalence of STD among blacks led some authors to highlight the possible role of racism as a risk factor for sexually transmitted infections. Racism can be seen as playing a role in unequal access to health care, both historically and currently,15 and in differential acceptability of the services provided.16 Racism also carries responsibility for poverty as a result of discrimination in education and employment. Thomas16 describes historical factors such as the mechanization of agriculture and northward migration of blacks in this context. The dif-ferential rates of incarceration of black men may be considered a form of institutionalized racism. Among the effects of these high rates of incarceration is the removal of men from the potential pool of sex partners; this affects sexual networks in ways that promote the spread of sexually transmitted infections.17
Poverty is strongly associated with STD prevalence. Although the mechanisms of action through which poverty affects STD are not clear, one potential mechanism that has been suggested is psychologic depression along with increased use of drugs and alcohol, which may increase risky sexual behavior. However, an examination of regional differences in these mental health factors18 failed to substantiate them as likely contributors to regional differences in STD. Sex trading for nondrug-related reasons, as well as other negative effects on sexual networks, remain possible poverty-related mechanisms of action in the relationship between poverty and STD prevalence.
Another factor related to poverty is the regional differentials in enrollment in the military. The southern states contribute to military service in numbers disproportionate to their population percentages19. Because military service provides employment, training, and educational benefits, it is not surprising that it attracts low-income individuals. Participation in the military is associated with high rates of HIV and STD internationally20 and domestically.21,22
Residence in rural or semirural environments may contribute to STD spread in several ways. First, access to health care, including prevention services, may be logistically difficult as a result of long distances. Second, stigma surrounding sexual behavior and disease is likely to be heightened in nonurban areas. Shame and fear of stigmatizing reactions on the part of neighbors may lead to reluctance to seek sexual health services in close-knit communities.23 Men who have sex with men (MSM) may be less likely to be open about their sexual behaviors in such communities and may concurrently be sexually involved with women, who in turn may be unaware of the risk posed to them by their partners' MSM behavior.24 However, it is unknown whether the prevalence of bisexual behavior or covert MSM behavior is elevated in rural communities or the South specifically. It has also been suggested that the prominence of the church, with its sexual prohibitions, intensifies fear of stigma (E. J. Brown, personal communication, 2003).
Three prevention intervention approaches are described in this volume. Two of them25,26 are particularly useful in situations in which concern about stigma may prevent people from seeking prevention services. One of these25 describes the use of mass media and social networks to influence norms and behavior. Mass media interventions may be deployed even in very rural contexts because they are independent of physical distance and access. Interpersonal communication often prompted by mass media material, which flows through social communication networks, is a necessary additional ingredient in fostering behavior change. Another intervention approach relies on structural change.26 Such approaches are also particularly useful in potentially stigmatizing contexts. Strategies such as increasing alcohol taxation do not induce stigma and have been shown to be effective in reducing STD incidence.27 Finally, Berman28 discusses the importance of STD treatment in reducing the transmission of HIV.
Rates of bacterial STD have declined in the South and elsewhere, and little is known about the geographic distribution of non-HIV viral STD. However, recent data suggest that HIV rates have soared among blacks, particularly in the rural areas of the South.29 This collection of papers is intended to stimulate future targeted research and intervention efforts into the epidemiology and prevention of HIV and other STD in these populations.
1.Karon JM, Fleming PL, Steketee RW, DeCock KM. HIV in the United States at the turn of the century: An epidemic in transition. Am J Public Health 2001; 91:1060–1068.
2.Farley TA. Sexually transmitted diseases in the Southeastern United States: Location, race, and social context. Sex Transm Dis 2006; 33:7 Supplement:S58–S64.
3.Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2001. Atlanta: US Department of Health and Human Services, September 2002.
4.Pisani E, Garnett GP, Brown T, et al. Back to basics in HIV prevention: Focus on exposure. BMJ 2003; 326:1384–1387.
5.Aral SO, Blanchard J, Moses S, Wasserheit J. Phase-specific strategies for the prevention, control and elimination of STDs. II. In: Program and abstracts of the 15th Biennial Congress of the International Society for Sexually Transmitted Disease Research (ISSTDR); Ottawa). Ottawa: ISSTDR, 2003:13–5.
6.Aral SO, Padian NS, Holmes KK. Introduction: Advances in multilevel approaches to understanding the epidemiology and prevention of sexually transmitted infections and HIV: An overview. J Infect Dis 2005; 191(suppl 1):S1–S6.
7.Aral SO. Determinants of STD epidemics: Implications for phase appropriate intervention strategies. Sex Transm Infect 2002; 78(suppl 1): i3–13.
8.Anderson RM, May RM. Infectious Diseases of Humans. Oxford: Oxford University Press, 1991.
9.Wasserheit JN, Aral SO. The dynamic topology of sexually transmitted disease epidemics: Implications for prevention strategies. J Infect Dis 1996; 174(suppl 2):S201–213.
10.Joint United Nations Programme on HIV/AIDS and World Health Organization (UNAIDS/WHO) Working Group on Global HIV/AIDS and STI Surveillance. Guidelines for Second Generation HIV Surveillance [WHO/CDS/CSR/EDC/2000.5; UNAIDS/00.03E]. Geneva: UNAIDS/WHO, 2000.
11.Kerani RP, Handcock MS, Handsfield HH, Holmes KK. Comparative geographic concentrations of 4 sexually transmitted infections. Am J Public Health 2005; 95:324–330.
12.Berman SM, Aral SO. The evidence base: Strengths, weaknesses and pitfalls. Abstract: Presented at the 16th Biennial meeting of the International Society for Sexually Transmitted Disease Research, Amsterdam, The Netherlands, July 10–13, 2005.
13.Aral SO. The social context of syphilis persistence in the southeastern United States. Sex Transm Dis 1996; 23:9–15.
14.Bishaw A. Areas With Concentrated Poverty: 1999. Washington, DC: US Census Bureau, 2005.
15.Smith DB. Racial disparities in care: The concealed legacy of a divided system. Sex Transm Dis 2006; 33:000–000.
16.Thomas JC. Commentary: From slavery to incarceration: Social forces affecting the epidemiology of STDs in the rural South. Sex Transm Dis 2006; 33:000–000.
17.Adamora A, Schoenbach VJ. HIV and African Americans in the southern United States: Sexual networks and social context. Sex Transm Dis 2006; 33:000–000.
18.O'Leary A, Broadwell SD, Yao P, Hasin D. Major depression, alcohol and drug use disorders do not account for the STD and HIV epidemics in the southern United States. Sex Transm Dis 2006; 33:7 Supplement:S70–S77.
19.Population Representation in the Military Services. Office of the Under Secretary of Defense, Personnel and Readiness. Washington, DC: Department of Defense, 2002.
20.Nopkesorn T, Mock PA, Mastro TD, et al. HIV-1 subtype E incidence and sexually transmitted diseases in a cohort of military conscripts in northern Thailand. J Acquir Immun Defic Syndr Hum Retrovirol 1998; 18:372–379.
21.Sutton TL, Martinko T, Hale S, Fairchok MP. Prevalence and high rate of asymptomatic infection of Chlamydia trachomatis
in male college Reserve Officer Training Corps cadets. Sex Transm Dis 2003; 30:901–904.
22.Gaydos CA, Howell MR, Quinn TC, McKee KT Jr, Gaydos JC. Sustained high prevalence of Chlamydia trachomatis
infections in female army recruits. Sex Transm Dis 2003; 30:539–544.
23.Lichtenstein B. Stigma as a barrier to treatment of sexually transmitted infection in the American deep south: Issues of race, gender, and poverty. Soc Sci Med 2003; 57.
24.Wheeler DP. Exploring HIV prevention needs for non-gay identified black and African American men who have sex with men: A qualitative exploration. Sex Transm Dis 2006; 33:7 Supplement:S11–S16.
25.Valente TW. Diffusion of innovations and network segmentation: The part played by people in promoting health. Sex Transm Dis 2006; 33:000–000.
26.Cohen DA, Wu SY, Farley TA. Structural interventions to prevent HIV/STD: Are they cost-effective for women in the southern US? Sex Transm Dis 2006; 33:7 Supplement:S46–S49.
27.Chesson HW, Harrison P, Stall R. Changes in alcohol consumption and in sexually transmitted disease incidence rates in the United States: 1983–1998. J Stud Alcohol 2003; 64:623–630.
28.Berman SM, Cohen MS. STD treatment: How can it improve HIV prevention in the South? Sex Transm Dis 2006; 33:000–000.
29.Fleming PL, Lansky A, Lee LM, Nakashima AK. The epidemiology of HIV/AIDS in the southern United States. Sex Transm Dis 2006; 33:7 Supplement:S32–S38.