Somboon Suprasert

Changes in Sexual Behavior and a Decline in HIV Infection among Young Men in Thailand

BACKGROUND In Thailand the epidemic of human immunodeficiency virus (HIV) infection is of recent origin. Because of the high seroprevalence of HIV among sex workers, the Ministry of Public Health began a program in 1990 and 1991 to promote the use of condoms during commercial sex. We evaluated the effect of this and other programs to prevent HIV infection in Thailand. METHODS Using direct interviews, we studied five cohorts of 21-year-old men from northern Thailand who were conscripted into the army by a lottery in 1991, 1993, and 1995. In all, 4311 men were tested for HIV antibodies by enzyme-linked immunosorbent assay, with confirmation by Western blot assay. RESULTS In the 1991 and 1993 cohorts, the prevalence of HIV infection was 10.4 to 12.5 percent. In 1995, it fell to 6.7 percent (P < 0.001). The seroprevalence was only 0.7 percent among men who did not have sexual relations with a sex worker before 1992. Over the study period, the proportion of men who reported having sexual relations with a sex worker fell from 81.4 percent to 63.8 percent (P < 0.001). From 1991 to 1995, the mens reported use of condoms during the most recent sexual contacts with sex workers increased from 61.0 percent to 92.5 percent (P < 0.001); and in 1995, 15.2 percent of men had a history of a sexually transmitted disease, as compared with 42.2 percent in 1991 (P < 0.001). CONCLUSIONS Public health programs in Thailand have led to substantial changes in sexual behavior among young men, especially an increased use of condoms, and the rate of new HIV infections has declined.

The association of herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and syphilis with HIV infection in young men in northern Thailand

To evaluate the association between sexually transmitted diseases that commonly may cause genital ulceration and prevalent and incident HIV infections, we conducted three case control studies in a cohort of 21-year-old male military conscripts in northern Thailand. The men were evaluated at baseline in 1991 and semiannually until their discharge 2 years later. Serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and HIV were more frequent at baseline in 83 men with a history of genital ulcer than in 97 men without such a history. Seropositivity to H. ducreyi (odds ratio [OR] = 3.46), HSV-2 (OR = 3.83), and syphilis (OR = 1.53) were more common in HIV-positive than HIV-negative men. Men (N = 45) who seroconverted to HIV while in the military were more often seropositive for H. ducreyi and HSV-2 before HIV seroconversion and also were more likely to seroconvert to HSV-2 and H. ducreyi during the same interval as their HIV seroconversion compared with men who remained HIV-negative. These data suggest that HSV-2 and H. ducreyi may be both markers for high-risk sexual behavior and risk factors for HIV infection among young men in Thailand.

Behavioral and sociodemographic risks for frequent visits to commercial sex workers among northern Thai men

Objective:The transmission of HIV-1 in Thailand has recently been attributed to exposure to infected commercial sex workers (CSW). We sought to identify risk factors for patterns of CSW visits among northern Thai men. Design:Retrospective recall of lifetime and recent CSW visits and associated risk factors were obtained by interview. Setting:Two military bases in northern Thailand. Participants:We enrolled two cohorts (n=2417) of young men, aged 19–23 years, who were conscripted into the Royal Thai Army and Air Force from six provinces in northern Thailand in May and November 1991. Main outcome measures:Frequency of self-reported lifetime and recent sex with CSW. Results:Multivariate results showed that lower socioeconomic status, early first intercourse and substance-use factors (alcohol, marijuana, other drugs, and smoking) associated with lifetime and recent sex with CSW. Sexual intercourse with other female partners, lower price paid at last CSW visit and frequency of condom use with CSW did not differentiate frequent from infrequent CSW visitors. Conclusions:Limits in the frequency of sex with CSW, improved condom practices and reduction of drinking prior to CSW visits would all appear to provide substantial protection from exposure to HIV-1 in this setting. AIDS 1993, 7:1647–1652

HIV-1 infection among lower class commercial sex workers in Chiang Mai, Thailand

Objective:To determine risk factors for HIV-1 infection in female commercial sex workers (CSW) in northern Thailand. Methods:A cross-sectional survey of female CSW from 11 sex establishments frequented by military conscripts that included an interview and serological testing for HIV-1. Results:The HIV-1 seroprevalence in 230 CSW was 65%; the rate was lower among CSW from Chiang Mai than from rural areas. Multivariate logistic regression analysis for HIV-1 included the following significant factors: non-urban location of the sex establishment, ethnic Thai lowlander, lower price, history of genital warts and dysuria. Condom use, number of partners and duration of employment were not significantly associated with HIV-1 prevalence after adjustment for other risk factors. Conclusions:The high level of HIV-1 seroprevalence in this sample demonstrates the risk of transmission in lower cost commercial sex encounters in northern Thailand. Non-Thais (ethnic Hill tribes and Burmese) had lower HIV-1 prevalence than ethnic Thais. Type of establishment (‘direct’ brothel-based or ‘indirect’ establishments) was not predictive of HIV-1 seroprevalence. However, rural establishments were less vigilant in promoting condom use, suggesting the need for renewed efforts to enforce the Ministry of Public Healths ‘100% Condom Campaign’ in commercial sex establishments.

Epidemiologic risk factors for incident sexually transmitted diseases in young Thai men

Background and Objectives: Prospective studies of incidental sexually transmitted diseases in developing countries rarely have been reported. As the human immunodeficiency virus epidemic widens, knowledge of the epidemiology of sexually transmitted diseases as co‐factors for human immunodeficiency virus infection is viewed as vitally important. Goal: To determine epidemiologic risk factors for incidental sexually transmitted diseases in young men in northern Thailand. Study Design: A cohort of 2,417 men selected by lottery for military conscription was followed an average of 22 months, with epidemiologic risk factors and sexually transmitted disease histories assessed semiannually. Sexually transmitted diseases were determined by physician or symptom histories obtained by interview. Results: Sexually transmitted disease incidence was 17.04 per 100 person‐years. Gonorrhea and chancroid were commonly reported, whereas incident syphilis was rare. Sexually transmitted disease incidence declined significantly in the 2‐year period. Most sexually transmitted diseases were acquired through commercial sex patronage. However, among men who did not report visiting a brothel, there was a significant increase in sexually transmitted diseases among men reporting sex with a girlfriend. Other risk factors included inconsistent condom use, drug use, and low educational level. Frequent alcohol use was associated with incident sexually transmitted diseases in bivariate analysis, but drinking at the time of last brothel visit was not associated with increased sexually transmitted diseases. Conclusions: Sexually transmitted disease control in Thailand is based on an integrated sexually transmitted disease clinic system. Many commercial sex workers are examined and treated routinely, but too infrequently to reduce sexually transmitted disease transmission between them and their male clients. Condom‐use levels in commercial sex settings still may be too low to reduce sexually transmitted disease transmission. More consistent and effective sexually transmitted disease treatment of commercial sex workers and their clients and education of men on the effective and consistent use of condoms is required to reduce the risks of sexually transmitted disease transmission in this population.