DESPITE THE EXISTENCE of long-standing sexually transmitted disease (STD) control programs, high rates of STDs continue to be a major public health challenge in some areas of the United States, especially in the South. The southern region of the United States has consistently reported higher rates of chlamydia, gonorrhea, and primary and secondary syphilis compared to other regions of the country. 1 In 2001, 6 of the 10 states with the highest rates of chlamydia were located in the South, and 8 of the 10 states with the highest rates of gonorrhea were in the South. In 2001, 403 (66%) of 606 U.S. counties with primary and secondary syphilis rates above the Healthy People 2010 objective were in the South. The reasons for the higher STD rates in the South are complex, but may be related to poverty and the availability of and access to healthcare services. 2 There is increasing evidence that many groups disproportionately infected with STDs have poor access to health care. 2,3 Based on these findings, STD control programs have initiated targeted screening programs for persons in high-risk groups. Such programs have been implemented in jails, emergency departments, and other nontraditional settings. 4,5,6 One such approach is the use of community-based screening and treatment programs in neighborhoods of high STD incidence. Community-based screening in nontraditional settings may facilitate STD screening for individuals who otherwise would not seek services, especially if they are asymptomatic. However, programmatic feasibility, community acceptance, and screening productivity must be considered as these interventions are developed.
In a previous study, we conducted surveys in areas with high STD incidence to determine the extent to which persons trusted public health officials’ approach to STD control and the extent to which these persons would participate in community-based screening and treatment programs. 7 Overall, respondents favored the provision of STD services in a mobile health van over services provided in a bar or in their home. Based on these findings, we instituted a community-based STD screening and treatment program as part of a multicomponent STD prevention initiative funded by the Centers for Disease Control and Prevention. Our objectives were 1) to evaluate the feasibility, acceptability, and yield of mobile community-based STD screening and treatment services in high STD incidence areas, and 2) to evaluate community attitudes toward mobile community-based STD screening and treatment services.
Methods
Mobile Screening Program
From March 1997 to April 2000, free, voluntary, and confidential screening and treatment for chlamydia, gonorrhea, HIV, and syphilis were conducted in high STD incidence neighborhoods of Baton Rouge, Louisiana, as part of the “Community Health Outreach Project” (CHOP). The CHOP project was a collaborative effort between the Louisiana Office of Public Health and two community-based organizations that were previously funded for HIV street-outreach prevention activities. A nurse, one phlebotomist (i.e., health department disease intervention specialist trained in phlebotomy), and two outreach workers staffed a 32-foot mobile STD clinic van. The van was designed for the provision of medical services and included an examination room, a phlebotomy station, and a private counseling room.
Syphilis cases that were reported to the health department and information obtained from local public health disease investigators concerning suspected illicit drug activity and prostitution were used to identify census tracts for mobile clinic screening events. The neighborhoods identified within these census tracts were predominantly lower socioeconomic, black communities that bordered petroleum and chemical industrial complexes. Settings for mobile screening events included stores, bars, restaurants, churches, vacant lots, and public housing facilities. Site selection was based on the amount of “foot traffic,” parking availability, and cooperation by the business owner. Approximately two screening and treatment events per week were scheduled over the 3-year period and advertised in advance with posters and flyers distributed in neighborhoods. To avoid stigmatizing clients, the project and screening events were advertised as the “Community Health Outreach Project,” in which various free health promotion activities took place, including screening for chlamydia, gonorrhea, syphilis, HIV, high blood pressure testing, and pregnancy testing. All participants gave oral informed consent for STD testing and treatment. Written consent was obtained for HIV testing. Testing was performed on a voluntary basis, and participants could choose which STDs to be tested for. Screening events were scheduled from 2:00 pm to 5:00 pm. However, services were provided to persons interested in being tested regardless of their time of arrival.
Laboratory Methods
Screening for syphilis was accomplished with the Venereal Disease Research Laboratory (VDRL) test; a microhemagglutination for Treponema pallidum (MHA-TP) was conducted if a VDRL test was positive. Urine specimens were tested for chlamydia and gonorrhea using the ligase chain reaction (LCR) assay (Abbott LCx; Abbott Diagnostics, Abbott Park, IL). HIV antibody testing also was done using an enzyme immunoassay (EIA) and a Western blot test if the EIA was repeatedly reactive.
Treatment and Follow Up
The Louisiana Department of Health and Hospital's standard of care for public STD clinic screening and treatment was followed. Persons testing positive for chlamydia, gonorrhea, or syphilis who were not treated based on symptoms at the time of screening were immediately notified of their results by telephone or by home visits and referred to the local health department for treatment. Health department personnel and members of the screening staff made repeated telephone calls and home visits to provide appropriate referrals for antimicrobial medication. Health department staff members conducted partner notification for those persons diagnosed with early syphilis and HIV infection. They also provided HIV posttest counseling of persons found to be HIV-positive and referred these individuals to HIV specialty clinics. Persons testing positive for chlamydia or gonorrhea were instructed to refer their sex partners to the local health department for testing and treatment. Persons testing positive for chlamydia, gonorrhea, or syphilis were treated with standard antibiotic regimens as recommended by the Centers for Disease Control and Prevention. 8 Persons with elevated blood pressure and females with positive pregnancy tests were referred either to the local health department or to the local public hospital for follow-up.
Data Collection
Demographic and behavioral data were obtained from persons requesting STD testing using a standardized self-administered survey. Information obtained included access to health care, type of health insurance, history of STDs, current medication use, recent STD/HIV testing, STD symptoms in the past three months, number of sex partners in past 12 months, and reported condom use during last sexual encounter.
Community Attitude Surveys
Community attitudes toward the project were assessed with street-intercept surveys 9 conducted in neighborhoods where mobile screening events had taken place. Outreach workers, trained in interviewing, conducted these interviews 2 weeks after screening events during the second and third years of the project. Respondents were eligible if they were aged 18 years or older and gave oral informed consent. Interviewers were instructed to approach all eligible respondents they saw who were anywhere within a one-block radius of the previous screening event. All interviews were conducted outdoors on weekdays, usually between 2:00 pm and 4:00 pm.
These surveys were designed 1) to determine whether persons had heard of the CHOP program or seen the CHOP van, 2) to assess what proportion of those having seen or heard of the program actually went to the van for services, 3) to evaluate the respondents’ experience with the van, and 4) to assess community attitudes about the health department's use of a mobile van for STD screening and treatment. All survey questions analyzed for this report were closed (i.e., responses provided). Responses were measured using either ordinal scales (e.g., “very good,” “good,” “okay,” “bad,” or “very bad”) or two-category scales (e.g., “yes” or “no”).
Data Analysis
Statistical analyses were performed using Epi Info software, Version 6.04 days. 10 Chlamydia, gonorrhea, and HIV positivity were calculated as the proportion of positive results out of the total number tested. Inadequate specimens and unsatisfactory laboratory results were excluded. Syphilis prevalence was calculated as the proportion of persons tested with positive results for both VDRL and MHA-TP tests and who had no history of previous syphilis. Statistical testing for differences between groups was performed using chi square or Fisher's Exact Test as appropriate, and continuous variables were evaluated by the Wilcoxon's rank sum test or by Student's t-test. 10
Results
Study Population
From March 1997 to August 2000, 256 community-based screening events were held at 110 sites in the greater Baton Rouge area. The mean number of persons screened per event was 13 (range 2–46). Of the 3375 participants screened through this program, 2092 (62%) were female, and 1283 (38%) were male (Table 1). The majority (93%) of participants identified themselves as black. Approximately 17% of male and female participants reported having had a sexually transmitted disease in the past. The occurrence in the last three months of at least one symptom consistent with a sexually transmitted infection (discharge, dysuria, sore on genitalia, or body rash) was reported by 303 of the 2092 female participants and by 137 of the 1283 male participants (14.5% versus 10.7%, P = 0.002). Self-reported condom use during last sexual encounter was higher for males than for females (48.8% versus 36.2%, P < 0.001). The mean number of reported sex partners in past 12 months was higher for male participants (3.4 versus 1.8, P < 0.001). Female participants were more likely than male participants to report having a “regular” doctor or clinic (57% versus 38%, P < 0.001).
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TABLE 1: Characteristics of Persons Attending a Mobile Clinic, Baton Rouge, LA, 1997–2000
STD Prevalence
During the study period, 3110 blood samples were collected for syphilis testing, of which 196 (6.3%) were VDRL positive. Thirty-seven (1.2%) MHA-TP confirmed tests were reactive for persons with no history of syphilis. Syphilis prevalence was 1.1% (21/1901) in female participants and 1.3% (16/1209) in male participants. Syphilis prevalence generally increased with age up through age 40 and then decreased (Table 2). Syphilis prevalence was 1.2% (18/1489) in participants who reported having a regular doctor and 1.3% (19/1505) in participants who reported not having a regular doctor. The prevalence of syphilis among participants who reported using a condom during their last sexual encounter was 1.4% (17/1236), compared to a prevalence of 1.2% (20/1723) among those who reported not using a condom.
TABLE 2: Prevalence of Sexually Transmitted Diseases by Laboratory Screening among Persons Seen at a Mobile Clinic, Baton Rouge, LA 1997–2000
Of 2807 blood samples collected for HIV testing, 70 (2.5%) were positive; 63 (2.2%) were positive for participants who did not report that they had previously tested positive. The overall HIV prevalence was higher in females than in males, and the prevalence generally increased with age (Table 2). Of the 50 HIV-positive women, 5 were coinfected with a bacterial STD; 2 of 20 of HIV-positive men were coinfected with a bacterial STD. HIV prevalence was higher in females who reported a history of syphilis (5.4% versus 2.3%, P = 0.06). Men with a history of syphilis had a higher HIV prevalence (4.4% versus 1.7%, P = 0.2).
Of the 2229 urine specimens, 185 (8.3%) were positive for Chlamydia trachomatis. Chlamydia prevalence was higher in females than in males (9.9% versus 5.5%, P < 0.01). Of female participants testing positive for chlamydia, 88.2% were asymptomatic; of males with chlamydial infection, 90.7% were asymptomatic. Chlamydial infection was found in 26 (12.6%) of 206 females with genitourinary symptoms, compared with 135 (10.2%) of 1321 females without these symptoms. Four (6.0%) of 67 symptomatic males were infected with chlamydia compared with 41 (5.5%) of 739 asymptomatic males. Chlamydial prevalence decreased with age (Table 2). Of 140 females with chlamydial infection, 26 (18.6%) were coinfected with gonorrhea. Of 45 males with chlamydial infection, 7 (15.6%) were coinfected with gonorrhea. Chlamydia prevalence was significantly lower among males who reported having a regular doctor or clinic (2.7% versus 6.2%, P < 0.05). The prevalence of chlamydia among females did not differ significantly between those who reported having a regular doctor and those who did not (8.9% versus 10.9%, P = 0.2).
Of 2224 urine samples, 108 (4.9%) were positive for Neisseria gonorrhoeae. Gonorrhea prevalence was similar in female and male participants (5.3% versus 4.1%, P = 0.2). Gonorrhea prevalence decreased with age (Table 2). Gonococcal infection was associated with symptoms in females (prevalence was 8.3% among those symptomatic versus 4.3% among those asymptomatic) and males (16.4% among symptomatic versus 2.3% among those asymptomatic), but 77% of females with gonorrhea and 67% of males with gonorrhea were asymptomatic. Of 75 females with gonorrhea, 26 (34.7%) were chlamydia coinfected and in the 33 males with gonorrhea, 7 (21.2%) were coinfected with chlamydia. The prevalence of gonorrhea was lower among males who reported having a regular doctor or clinic (2.3% versus 4.9%, P = 0.09). The prevalence of gonorrhea among females who reported having a regular doctor was 5.2% (38/730) compared to a prevalence of 5.6% (36/638) among females that reported not having a regular doctor.
Health department personnel documented antibiotic treatment for over 90% of the 330 bacterial sexually transmitted infections diagnosed. The remaining 10% were either unlocatable or refused treatment. Of the 63 persons newly diagnosed as having HIV infection, notification of their results and posttest counseling was performed for 80%.
Community Surveys
Of the 389 respondents, 217 (56%) were female and 172 (44%) were male. Ages ranged from 18 to 73, with a mean age of 30. The majority (97%) of respondents identified themselves as “black” and 3% identified themselves as “white.” The majority of respondents (56%) reported that they were single, 19% said that they lived with their partner, 16% said that they were married, 7% said they were divorced, and 2% were widowed.
Of 389 street-intercept surveys conducted to assess community perceptions about mobile STD screening, 377 respondents (97%) thought neighborhood testing was a “good” or “very good” idea, and only 2 (1%) thought it was a “bad” idea; 256 (65%) had heard of the CHOP program, and 287 (73%) had seen or heard of the “health van” in their neighborhood. Of the 287 respondents who had seen or heard of the van, 175 (61%) used the van for health services, of whom 163 (96%) reported having had a “good” or “very good” experience. When asked whether one would use a van in their neighborhood for STD testing services, 338 (87%) respondents said “yes.”
Respondents also were asked about which organizations they trusted most to implement “a new program to control syphilis.” The public STD clinic was trusted “very much” by 48% of respondents. The only providers trusted to a greater extent were private physicians and private hospitals, trusted “very much” by 63% and 59% of respondents, respectively. The two community-based organizations working with STDs and HIV in the Baton Rouge area were trusted “very much” by 22% of respondents. When respondents were asked about health department partner notification efforts for STDs, 368 of 389 (95%) respondents said partner notification was either a “good” or “very good” idea.
Discussion
We found that the mobile, community-based STD screening and treatment program was feasible to implement, identified many sexually transmitted infections, and was acceptable to community members. We estimated that 350 sexually transmitted infections were detected through community-based mobile clinic screening during a 3-year period. Many of the individuals infected with an STD were asymptomatic and were therefore unlikely to have sought medical care had these services not been easily accessible. In addition, our mobile screening program focused on areas of Baton Rouge that were known for prostitution and drug use activity; this may, in part, explain the high STD prevalence found. Such an approach may be a way to provide services to those groups that it is important to reach for disease control purposes, but that are unlikely to seek traditional medical care. 11
Our finding of high rates of asymptomatic STDs in an urban high STD incidence community setting is consistent with the findings of other nontraditional screening programs in other urban areas. High STD rates in arrestees have been found in corrections facilities in Chicago, Birmingham, Baltimore, Nashville, and Los Angeles. 12–14 However, there are fewer reports of community-based screening programs. In St. Louis, Missouri, Jones et al. reported gonorrhea or chlamydial infection, or both, in 24 of 277 (8.7%) persons screened at 20 community-based organizations. 6 Marrazzo et al. 15 found that 8.6% of adolescent girls screened through a variety of community-based settings in Seattle, Washington, were positive for chlamydial infection. A screening program in Denver, Colorado, found that youth screened in a nonclinical facility-based setting had a chlamydia prevalence of 4.4%, as compared with a prevalence of 11.9% in field-based settings. 16 In 1998 Gunn et al. 17 reported that, of 261 male teens screened in field settings, 16 (6.1%) were positive for chlamydia. Our program differs in that we used a mobile van, targeted multiple high-incidence communities, and offered a variety of STD and other health services.
Implementing targeted mobile screening programs may present economic and logistical challenges. Our program was implemented with existing health department personnel (i.e., disease intervention specialists) and staff members of the community-based organizations, and it required hiring only one full-time nurse. Obtaining and maintaining a suitable vehicle may be the greatest barrier that local health departments face when implementing this type of initiative. The Louisiana Office of Public Health originally purchased the 32-foot mobile van used by this program to aid with natural disasters. When not in use for that purpose, both the STD control program and the immunization program utilized the vehicle for public health outreach. Future studies of nontraditional screening programs should include cost-effectiveness analyses.
Although difficult to measure, a key component to the success of this program was the collaboration between the local health department and the two funded community-based organizations. Despite relatively low levels of trust among community members in the community-based organizations, it appears that existing relationships between CBO outreach workers, health department personnel, and key community members in the high incidence areas targeted for mobile screening fostered community trust and support of the project. We believe that existing relationships with the community at risk also helped to garner community buy-in, and to some extent, ownership of the project.
We found that community members were generally in favor of the health department-sponsored mobile screening and treatment project. One important, unforeseen outcome of this project was the strengthening of the relationship between communities at risk and the local health department. Clearly, we identified a segment of the population that was at risk for STDs. The population reached by our mobile screening initiative is probably at risk for other preventable infectious and chronic diseases. Mobile, community-based STD screening and treatment programs should be considered in other areas of the United States where high-incidence neighborhoods can been identified.
We thank our partners at the Louisiana Office of Public Health, Nolan Richardson and Jim Scioneaux, and at the Metro Health Education, Christopher Jackson, Elizabeth Woolery, and Billy Davis.
REFERENCES
1. Centers for Disease Control, Prevention.
Sexually transmitted disease surveillance, 2001. Atlanta: U.S. Department of Health and Human Services, September 2002.
2. Institute of Medicine, Committee on Prevention and Control of Sexually Transmitted Diseases. The hidden epidemic: confronting sexually transmitted disease. Eng TR, Butler WT, ed. Washington, DC: National Academy Press, 1997.
3. Farley TA, Kahn RH, Johnson G, Cohen DA. Strategies for syphilis prevention: findings from surveys in a high-incidence area. Sex Transm Dis 2000; 27: 305–310.
4. Blank S, McDonnell DD, Rubin SR, et al. New approaches to syphilis control: finding opportunities for syphilis treatment and congenital syphilis prevention in a women's correctional setting. Sex Transm Dis 1997; 24: 218–226.
5. Todd CS, Haase C, Stoner BP. Emergency department screening for asymptomatic sexually transmitted infections. Am J Public Health 2001; 91: 461–464.
6. Jones CA, Knaup RC, Hayes M, Stoner BP. Urine screening for gonococcal and chlamydia infections at community-based organizations in a high-morbidity area. Sex Transm Dis 2000; 27: 146–151.
7. Kahn RH, Mosely KE, Johnson G, Farley TA. Potential for community-based screening, treatment, and prophylaxis for syphilis prevention. Sex Transm Dis 2000; 27: 188–192.
8. Centers for Disease Control, Prevention. 1998 guidelines for treatment of sexually transmitted diseases. MMWR 1998; 51(RR-06): 1–80.
9. Miller KW, Wilder LB, Stillman FA, Becker DM. The feasibility of a street-intercept survey method in an African-American community. Am J Public Health 1997; 87( 4): 655–658.
10. Dean AG, Dean JA, Coulombier D, et al. Epi Info, Version 6. A word processing, database, and statistics program for epidemiology on microcomputers. Atlanta: Centers for Disease Control and Prevention, 1994.
11. Plummer FA, Coutinho RA, Ngugi EN, Moses S. Sex workers and their clients in the epidemiology and control of sexually transmitted diseases. In: Holmes KK, March PA, Sparling PF, et al., ed. Sexually Transmitted Diseases. 3rd ed. New York: McGraw-Hill, 1999; 143–147.
12. Mertz KJ, Schwebke JR, Gaydos CA, Beidinger HA, Tulloch SD, Levine WC. Screening women in jails for chlamydial and gonococcal infection using urine tests: feasibility, acceptability, prevalence, and treatment rates. Sex Transm Dis 2002; 29( 5): 271–276.
13. Rogers WB, Seigenthaler CP. Correctional health care as a vital part of community health. J Amb Care Management 2001; 24( 3): 45–50.
14. Cohen D, Scribner R, Clark J, Cory D. The potential role of custody facilities in controlling sexually transmitted disease. Am J Public Health 1992; 82: 552–556.
15. Marrazzo JM, White CL, Krekeler B, et al. Community-based urine screening for
Chlamydia trachomatis with a ligase chain reaction assay. Ann Intern Med 1997; 127( 9): 796–803.
16. Rietmeijer CA, Yamaguchi KJ, Ortiz CG, et al. Feasibility and yield of screening urine for
Chlamydia trachomatis by polymerase chain reaction among high-risk male youth in field-based and other nonclinic settings. A new strategy for sexually transmitted disease control. Sex Transm Dis 1997; 24( 7): 429–435.
17. Gunn RA, Podschun GD, Fitzgerald S, et al. Screening high-risk adolescent males for
Chlamydia trachomatis infection. Obtaining urine specimens in the field. Sex Transm Dis 1998; 25( 1): 49–52.
