The prevalence of sexually transmitted diseases (STDs) declined sharply among migrant workers in a South African mining community as well as among high-risk women living near the mines after monthly curative and preventive services were provided to the women. Among women who made at least three visits to a free clinic set up in the community, rates of gonorrheal and chlamydial infection dropped from an initial 15% and 14%, respectively, to 8% and 3% by their third clinic visit.1 Over the same period, the prevalence of one or both diseases among male migrant workers decreased from 11% to 6%, while the prevalence of genital ulcers dropped from 6% to 1%.

The clinic in a Free State mining town provided treatment and preventive services to female commercial sex workers and women with a high number of sexual partners from October 1996 through June 1997. The clinic was positioned near three single-sex mining hostels with a population of around 3,700 and within 2-4 kilometers of two more hostels. Two additional hostels were located more than five kilometers from the clinic.

Trained peer educators distributed clinic referral cards to women who frequented areas where miners were known to relax after work and encouraged them to attend the clinic on a monthly basis. At first visit, all referred women were assessed and treated for STDs. Those who reported being commercial sex workers or having at least three regular or intermittent sex partners were enrolled in the study.

Upon enrollment, each woman completed a questionnaire about her demographic and obstetric characteristics, sexual history and current STD symptoms. Participants received a genital examination and provided urine samples for chlamydia and gonorrhea testing. Syphilis tests were also administered. All women received prevention education and free condoms and were treated presumptively for chlamydia, gonorrhea and genital ulcers with a one-gram dose of an antibiotic. Women with STD symptoms received additional treatment. The protocol at monthly follow-up visits mirrored that at baseline.

At the study's inception, miners living in hostels near the mobile clinic were tested for STDs at the mine hospital, as part of their annual preleave physical examinations; they were tested again nine months later. Urine samples were tested for chlamydia and gonorrhea; men with positive results and those with genital ulcers were treated. The researchers had access to mine hospital records of outpatient visits for the period December 1995 to June 1997. The total number of these visits were compared with the average number of STD visits for each hostel for the periods December 1995 to June 1996 and December 1996 to June 1997.

A total of 407 women attended the mobile clinic at the start of the study, 235 of whom returned more than once and 172 of whom returned at least three times. Women who remained in the study for at least three clinic visits were, on average, 33.9 years old. Of those who had regular partners, the mean number was 1.9; 26% had ever used a condom with a regular partner. Some 65% had previously been infected with an STD; 43% had not sought treatment. Twenty-six percent of women who made at least three visits reported being commercial sex workers; these women averaged 2.3-2.4 clients per day. Although 32% of the sex workers who made three or more visits reported using condoms sometimes, only 7% had used one on their most recent day of work.

At the start of the study, 17% of women were diagnosed with gonorrhea and 14% had a chlamydial infection. Twenty-five percent of women had one or both of these infections and 6% had symptomatic genital ulcers caused by a bacterial infection. The prevalence of STDs dropped with each successive clinic visit. Rates of gonorrheal and chlamydial infection fell to 8% and 4%, respectively, among women making their second visit, and to 5% and 1% among those attending the clinic a fourth time. In addition, the prevalence of symptomatic ulcers dropped to 2% among women making a second visit and to fewer than 1% among women making a fourth visit.

In the subset of women who attended the clinic three or more times, initial rates of gonorrhea and chlamydia were 15% and 14%, respectively; 10% had genital ulcers. The prevalence of gonorrheal and chlamydial infections dropped to 10% and 5%, respectively, among women making their second visit and to 8% and 3% among women making a third visit. The prevalence of symptomatic ulcers fell to fewer than 1% among women making a second visit and then rose to 1% of women making a third visit.

According to self-reports, the proportion of sex workers who used condoms with all clients during the last working day before their clinic visit increased steadily from 2% among those making their first visit and 7% at the second visit to 28% at the third visit and 33% at the fourth visit. Condom use with regular partners did not change significantly.

Among miners, the prevalence of chlamydial infections decreased significantly, from 7% at the initial visit to 4% nine months later. A small decrease in the rate of gonorrheal infection (from 5% to 3%) was not statistically significant. The proportion of men with one or both of these infections declined significantly, from 11% to 6%. The prevalence of genital ulcers also dropped, from 6% to 1%.

Data from the mine hospital suggested that the decrease in STD rates was particularly strong among men living in the hostels nearest to the mobile clinic. Among men living in the immediate vicinity of the clinic, the proportion seeking care for STDs at the hospital fell by 22% from the period between December 1995 through June 1996 to the comparable period a year later. Visits for STD care among men living 2-4 kilometers away from the mobile clinic declined less sharply (9%) over the same period. In contrast, the proportion of men living five or more kilometers from the intervention site who sought STD care increased by 34%.

The authors of an accompanying editorial point out that this program was carried out in a population that remained in one site for months at a time, and that it might not produce similar declines if transferred to a less stable environment, such as a port city or an urban transport route.2 They also note that mobile clinics and monthly mass treatment may not be feasible or affordable in all settings. They conclude, however, that the study results "illustrate the importance of bringing services to those who need them, especially in areas with marginalized and disempowered residents."--I. Olenick


1. Steen R et al., Evidence of declining STD prevalence in a South African mining town community following a core-group intervention, Sexually Transmitted Diseases, 2000, 27(1):1-7.

2. Van Dam J and Holmes KK, Effectively reaching the core and a bridge population with a four-component intervention, editorial, Sexually Transmitted Diseases, 2000, 27(1):9-11.