Pulmonary tuberculosis among patients visiting a voluntary confidential counseling and testing center, Cambodia.

SETTING: Voluntary counseling and confidential testing center (VCCT), Battambang District, Cambodia. OBJECTIVES: To determine newly diagnosed pulmonary tuberculosis (PTB) prevalence and predicting factors, and assess the utility of TB-related symptoms and yield of sputum microscopy and culture. DESIGN: Cross-sectional survey using interview, sputum smears and cultures and human immunodeficiency virus (HIV) testing. RESULTS: Of 496 participants, 29 (5.8%) had culture-confirmed PTB while 19 (65.5%) were acid-fast bacilli (AFB) smear-positive. PTB prevalence was higher (P < 0.001) in HIV-positives (20/124, 16.1%) than in HIV-negatives (9/372, 2.4%). On multivariable analysis, being HIV-positive, underweight (body mass index <18.5 kg/m(2)), rapid weight loss and age > or =35 years were predictors of PTB. Fever (93%) and hemoptysis (86%) had the highest sensitivity and specificity, respectively. The symptom complex of rapid weight loss, fever and hemoptysis detected all PTB cases (sensitivity 100%). Examination of three sputum smears with culture of the first sample detected 95% (19/20) of the HIV-associated PTB cases and 90% (26/29) overall. CONCLUSIONS: TB is common in the VCCT setting, regardless of HIV status. The high prevalence of HIV and PTB among the participants warrants consideration of TB screening for all HIV suspects. Such screening through VCCT is feasible. Adding a single culture test to the evaluation of an initial sputum sample set will substantially increase case detection.

Perceived social environment and quality of life among people living with HIV/AIDS in northern Thailand.

Efforts have been made to improve the social environment of people living with HIV/AIDS (PLWHA) in Thailand but have not been assessed in terms of their quality of life (QOL). In this study, we preliminarily examined the relationship between PLWHA's perception of social environment and QOL. The participants of this study were 200 PLWHA who belonged to the self-help groups in Chiang Mai province, northern Thailand. We collected data in face-to-face interviews using a structured questionnaire. The QOL was measured using a Thai version of the Medical Outcomes Study HIV Health Survey. Those who perceived themselves as well accepted by the community, perceived health services accessible or someone's help available, tended to have better QOL in terms of mental health. Community acceptance was most significantly related to QOL. Stratified analyses revealed similar relationships between perceived social environment and QOL among symptomatic and non-symptomatic participants but the relationships appeared weaker among men than women. In sum, our preliminary findings suggest that supportive social environment, especially community acceptance, is important for mental aspects of PLWHA's QOL irrespective of the disease stages and for women who usually take on multiple roles in the Thai traditional family.

HIV incidence and risk behaviours after voluntary HIV counselling and testing (VCT) among adults aged 19-35 years living in peri-urban communities around Chiang Mai city in northern Thailand, 1999.

The Thai government began HIV voluntary counselling and testing (VCT) in all provinces in 1992. We evaluated HIV incidence after participants utilized VCT and its effect on risk behaviours among northern Thai adults aged 19-35 years. A total of 924 men and 1,327 women volunteered to participate in the study. Subjects were counseled, interviewed (socio-demographic, HIV risk behaviour, and HIV testing history), and tested for HIV infection at baseline and at 6 months follow-up. All participants were provided group pre-test counselling; HIV test results were provided in individual confidential post-test counselling. Overall, 329 of 391 men and 621 of 669 women who reported a prior HIV test before participating in our study reported negative results at the previous test. Of these, nine men and 13 women tested positive at baseline, giving incidence rates of 1.04 and 0.69 per 100 person years (PY), respectively. Recent risk behaviour was rare; as a result, the effects of VCT on risk behaviours among the study participants could not be determined. The HIV incidence after VCT among this study population is substantial. Studies to investigate factors associated with HIV incidence among VCT clients could provide insights for more effective HIV prevention.

Lifetime correlates associated with amphetamine use among northern Thai men attending STD and HIV anonymous test sites.

AIMS: To investigate the demographic, sexual, and other substance use risk correlates of amphetamine use among men in northern Thailand prior to the current epidemic of amphetamine use in the Kingdom. DESIGN: Cross-sectional quantitative behavioral questionnaires. SETTING: Thai Ministry of Health STD and HIV Anonymous Test Sites in the upper northern provinces of Chiang Mai and Lamphun. PARTICIPANTS: Adult Thai men recruited at clinics for enrollment in an HIV seroincidence cohort study (The Thai HIVNET). All men were HIV negative at enrollment, and had at least one self-reported sexual risk for HIV infection (a recent STD, use of sex workers, multiple sexual partners, low or absent condom use, sex with men). MEASUREMENTS: Participants answered a structured questionnaire. FINDINGS: Lifetime history of amphetamine use was reported by 133/914 men, 14.5%. Older age was protective for use (odds ratio (OR) 0.5) and use was associated with use of other substances; heroin (OR 7.1), thinner (OR 6.2), opium (OR 5.9), and marijuana (OR 5.7). Several STDs were associated with amphetamine use: gonorrhea (OR 2.3) and genital warts (OR 2.4), and any STD (OR 1.9). In multivariate analysis, use of heroin (OR 3.1), soft drugs (OR 4.9), and a history of gonorrhea (OR 2.0) were independently associated with amphetamine use in northern Thai men. CONCLUSIONS: Associations between young age, gonorrhea, other substance use and amphetamines indicate that prevention measures could occur at STD clinics and be incorporated into school programs when individuals are entering adolescence.

Seroprevalence and subtype distribution of hepatitis C virus among blood donors and intravenous drug users in northern/northeastern Thailand.

The prevalence of antibodies against hepatitis C virus (HCV) and the distribution pattern of HCV subtypes were analyzed among healthy blood donors and intravenous drug users (IVDUs) in northern/northeastern Thailand. The prevalence of anti-HCV antibodies was 3.2% (26/820) among blood donors in Khon Kaen, while it was 90% (71/79) among IVDUs in Chiang Rai. HCV RNA was detected in all anti-HCV-positive sera collected from blood donors and IVDUs tested, as determined by reverse transcription-PCR analysis. Sequence analyses of amplified fragments of the HCV genome revealed that in Khon Kaen and Chiang Rai, Thailand, HCV-3a (50-60%) was the most common HCV subtype, followed by HCV-1a, HCV-1b, and subtypes of clade 6, each at 10-20%.

Epidemiologic and biologic characterization of a cohort of human immunodeficiency virus type 1 highly exposed, persistently seronegative female sex workers in northern Thailand. Chiang Mai HEPS Working Group.

Characterization of persons highly exposed to human immunodeficiency virus (HIV)-1 who remain uninfected may help define protective immunity. Seventeen HIV-1-seronegative Thai female sex workers (CSWs) with epidemiologic evidence of exposure to HIV-1 were studied for humoral immune responses and phenotypic and genotypic analyses of HLA class I and CCR5 allelic profiles. Infected CSWs and low-risk HIV-1-seronegative Thai women were controls. Highly exposed, persistently seronegative (HEPS) CSWs did not differ from HIV-infected CSWs in HIV risks, condom use, or sexually transmitted diseases. Significant differences were seen in humoral immune responses: gp160-specific IgA responses were detected in cervicovaginal lavage fluids in 6 of 13 HEPS CSWs but 0 of 21 seronegative subjects. All women had wild-type CCR5. HEPS CSWs were more likely to have the HLA-B18 phenotype and genotype than were matched controls (corrected P=.018). Epidemiologic exposure to HIV-1 without apparent infection, an unusual distribution of HLA class I alleles, and HIV-1 gp160-specific IgA responses suggest a biologic basis for this phenomenon.

Diversification of subtype E human immunodeficiency virus type 1 env in heterosexual seroconverters from Northern Thailand.

The C2-V3 region of the human immunodeficiency virus (HIV)-1 env was determined from 15 northern Thailand seroconverters between 1993 and 1995. Similar sequences were also determined from 18 seroconverting injection drug users in Baltimore. All seroconverters from northern Thailand were infected with subtype E HIV-1 on the basis of env sequences. Intersubject viral DNA distances increased from 2.3% in asymptomatic HIV-1-infected subjects characterized between 1990 and 1992 to 7.8% in these more recent seroconverters from Thailand. On the other hand, sequences from 18 seroconverters from Baltimore had a mean intersubject distance of 13.2%. The genetic diversity within HIV-1 subtype E in seroconverters in Thailand has increased significantly but is still less than that observed in HIV-1 from seroconverters in the United States, where the epidemic of HIV-1 infection is more mature. These results suggest that continued monitoring of the molecular epidemiology of HIV-1 infection in Thailand will be important for HIV vaccine development and evaluation.

Molecular methods for the diagnosis of genital ulcer disease in a sexually transmitted disease clinic population in northern Thailand: predominance of herpes simplex virus infection.

A multiplex polymerase chain reaction (M-PCR) assay that simultaneously detects the three major causes of genital ulcer disease (GUD), Haemophilus ducreyi, Treponema pallidum, and herpes simplex virus, was used to evaluate swab specimens for 38 sequential patients with GUD at a Thai sexually transmitted disease clinic. Subjects received clinical diagnoses and syndromic treatment. Swab specimens for H. ducreyi cultures and M-PCR were obtained. No H. ducreyi cultures were positive. Of 38 M-PCR specimens, 31 (81.6%) were positive for HSV, 1 (2.3%) for both HSV and T. pallidum, and none for H. ducreyi or T. pallidum alone; 6 (15.8%) were negative for all 3 pathogens. Clinical diagnoses corresponded poorly to M-PCR findings; none of 5 suspected cases of chancroid were positive by M-PCR and none of 1 for syphilis, but 21 of 24 suspected herpes lesions were confirmed by M-PCR. Human immunodeficiency virus infection status was known for 24 of 38 subjects; 11 (45.8%) were seropositive, and all 11 had HSV by M-PCR. HSV appeared to be the most common pathogen overall.

The molecular epidemiology of HIV-1 among male sex workers in northern Thailand.

Male commercial sex workers (CSWs) in northern Thailand are at high risk for HIV-1 infection and may be exposed to multiple subtypes of HIV-1 through sexual contact with men and women from Thailand, other Asian nations, and the West. We studied 103 male Thai nationals working in gay bars and clubs in Chiang Mai city who participated in the 1994 sentinel surveillance of the Thai Ministry of Public Health using HIV serologic testing, DNA polymerase chain reaction methods, molecular cloning, differential colony hybridization, nucleotide sequencing, and a third hypervariable region (V3) peptide enzyme-linked immunoabsorbent assay to differentiate subjects infected with HIV-1 subtypes B, E, both, or neither. The majority (58%) reported heterosexual orientation, and 35 (34%) were married. Seventeen (16.5%) were HIV infected: 16 (94%) of 17 had HIV-1 subtype E; 1 had HIV-1 subtype B. Two subjects had dually reactive results by molecular techniques but colony hybridization sequencing revealed only HIV-1 subtype E. HIV-1 subtype E appears to be the predominant clade among male CSWs in northern Thailand. This may have important implications for the global kinetics of the HIV epidemic.

PIP: Male prostitutes in northern Thailand are at high risk for HIV-1 infection and may be exposed to multiple subtypes of HIV-1 through sexual contact with men and women from Thailand and elsewhere. Blood samples of 103 male Thai nationals working in gay bars and clubs in Chiang Mai collected during the Thai Ministry of Public Health's 1994 sentinel surveillance were studied to determine the prevalences of HIV-1 subtypes B and E in the population. The men reported having an average of 2.5 male clients per week and had been in the business from 1 month to 7 years, with a median duration of 4 months. HIV serologic testing, DNA polymerase chain reaction methods, molecular cloning, differential colony hybridization, nucleotide sequencing, and a third hypervariable region (V3) peptide enzyme-linked immunoabsorbent assay were used to differentiate subjects infected with HIV-1 subtypes B, E, both, or neither. 58% of the men reported a heterosexual orientation outside of work and 34% were married. 72.1% reported inconsistent or no condom use with sex partners. 17 (16.5%) were infected with HIV. Of those infected, 16 (94%) had HIV-1 subtype E and 1 had subtype B.

Sexually transmitted disease prevalence in brothel-based commercial sex workers in Chiang Mai, Thailand: impact of the condom use campaign.

One hundred and ninety five (195) brothel-based commercial sex workers (CSW) in Chiang Mai, Thailand, were screened for sexually transmitted disease (STD) between October 1994 and April 1995, prior to their enrollment in a multi-center comparative trial of the effectiveness of two strategies using male and female condoms. These CSW had a mean age of 22.2 (SD 4.3) years. Forty-seven per cent were Thai and 57.4 per cent had no formal education. Median duration of prostitution was 16 months and median cost for sexual service was 50 baht (US$ 2) per client. Ninety-four per cent of CSW reported always using condoms with clients. There were 63 (32.3%) CSW infected with at least one type of the STD screened. The prevalence of STD included chlamydial infection (16.9%), gonococcal infection (14.4%), condyloma accuminata (4.6%), moluscum contagiosum (2.6%) and trichomoniasis (1.0%). There was no statistically significant risk factor for STD found in this study. Despite an active programme for prevention of STD in CSW and the provision of free condoms, STD were diagnosed in one-third of the screened CSW in Chiang Mai. The programme needs to be strengthened by more intensive education and practice in the correct and consistent use of condoms and integrated with other STD prevention programmes.

PIP: 195 brothel-based commercial sex workers (CSWs) in Chiang Mai, Thailand, were screened for sexually transmitted diseases (STDs) between October 1994 and April 1995, prior to their enrollment in a multi-center comparative trial of the effectiveness of two strategies using male and female condoms. These CSWs had a mean age of 22.2 (SD 4.3) years. 47% were Thai and 57.4% had no formal education. Median duration of prostitution was 16 months and median cost for sexual service was 50 baht (US$2) per client. 94% of the CSWs reported always using condoms with clients. 63 (32.3%) CSWs were infected with at least one of the screened STDs. The prevalence of STDs was as follows: chlamydial infection (16.9%), gonococcal infection (14.4%), condyloma accuminata (4.6%), moluscum contagiosum (2.6%), and trichomoniasis (1.0%). There was no statistically significant risk factor for STDs found in this study. Despite an active program for prevention of STDs in CSWs and the provision of free condoms, STDs were diagnosed in one-third of the screened CSWs in Chiang Mai. The program needs to be strengthened by means of more intensive education and correct and consistent use of condoms and integrated with other STD prevention programs.

Multiple condom use and decreased condom breakage and slippage in Thailand.

There is compelling evidence that male condoms effectively prevent transmission of sexual pathogens, including HIV-1. Condom breakage and slippage reduce this effect. We measured rates of condom slippage and breakage during heterosexual commercial sex in northern Thailand. Of 7,594 condoms examined in 4,734 client visits (5,040 sex acts), breakage was noted in 1.8% of single condom use (49.3% of acts), as compared with 0.2% with two condoms (49% of sex acts), and no breaks with more than two condoms (1.2% of sex acts). These breakage rates declined from 5.9% in a similar 1992 study in which 2.8% of sex acts were with more than one condom used at a time. Slippage occurred in only 0.1% of sex acts. Case-control analysis indicated that multiple clients, younger aged clients, sex after midnight, and high intensity (rough) sex were associated with condom breaks. The decline in breakage may be attributable to greater expertise in condom use by sex workers and clients, in response to the successful Thai national "100% Condom Campaign." Use of more than one condom during sex has been initiated by sex workers and their clients, a community response to condom promotion messages and fears of HIV infection. These data demonstrate the potential of condom use for high efficacy in reducing exposure to HIV-1 and other STDs. If condom use in commercial sex remains high, HIV incidence may decline among Thai men.

PIP: During August-October 1995, in northern Thailand, laboratory personnel examined 7594 condoms from 4734 client visits and 5040 sexual acts to evaluate mechanisms of condom breakage and slippage among 68 female commercial sex workers (CSWs) (mean age, 25 years) in 7 brothels in Lamphun City in Lamphun Province in order to verify condom use self-reports among the CSWs and to identify targets for interventions to reduce condom failure. Sexually transmitted disease (STD) episodes in the last year among the CSWs were gonorrhea (45.6%), pelvic inflammatory disease (29.4%), genital ulcer (29.3%), syphilis (13.2%), nongonococcal cervicitis (13.2%), and genital warts (8.8%). A condom was not used during 0.6% (30) of the sexual acts. 99.4% (5010) of the sexual acts involved use of at least one condom. There were only 5 condom slippage events--a condom slippage rate of 0.1%. This rate did not vary with the number of condoms used per sexual act. On the other hand, the condom breakage rate decreased as the number of condoms used per sexual act increased (1 condom = 1.8%; 2 condoms = 0.2%; 3-4 condoms = 0). Single condom use was more likely to yield breakage than multiple condom use (odds ratio [OR] = 11.4). The condom breakage rate 1 year after initiation of the 100% Condom Campaign (1992) was 5.9% compared to 1% in 1995. Condom breaks occurred just below the reservoir (40.2%), at reservoir tips (31.7%), along the shaft (18.3%), and at the base (9.8%). Multiple condom use increased from 2.8% to 50.4% during 1992-95. Factors independently associated with condom breaks included high-intensity (rough) sex (OR = 8.49; p 0.0001), more than one sexual act with the same client on the night of the breakage (OR = 2.72; p = 0.02), and sexual service after midnight (OR = 2.58; p = 0.03). These findings suggest that multiple condom use significantly contributed to the decline in condom breakage among multiple users. Another strong possible factor was greater skill in condom use by CSWs and by clients in response to the 100% Condom Campaign. Multiple condom use may reduce exposure to HIV-1 and other STDs.

Feasibility of northern Thai factory workers as participants in HIV vaccine trials.

To determine the feasibility of establishing a cohort of HIV-1 seronegative factory workers for potential HIV vaccine trials, and other HIV preventive interventions, we enroled and followed 499 male and female industrial workers in Lamphun Province, northern Thailand. A baseline demographic and HIV seroprevalence survey was conducted by a mobile team at worker's housing units in Lamphun Province in 1994. Follow-up HIV and syphilis incidence rates were measured 6 months later. The study was voluntary, anonymous, and included HIV pre- and post-test counseling, HIV and syphilis serology, and a self-administered fact sheet. A total of 106 men and 393 women were recruited. The median age was 22 years, and the mean 23.4 years. Educational levels were moderate; 41.9% had some secondary school and 23.6% had completed secondary school. HIV prevalence was 2.4% overall but differed by sex; among men it was 7/106, 6.6%, among women 5/393, 1.3%, OR = 5.49 (95% CI = 1.52, 20.39). Low educational levels were associated with HIV infection, OR = 7.2 (95% CI = 2.2, 23.4). Syphilis prevalence was 3.8%. Follow-up at 6 months was successful for 420/499 subjects, 84.2%, and varied by sex: 73/106 men, 68.9%, returned while 347/393 women, 88.3%, did so, RR = 1.21 (95% CI = 1.07, 1.37). There were 5 incident HIV-1 infections, a rate of 2.1/100 person years. The HIV seroconversion rate differed by sex, but not significantly; it was 4.1/100 person years for men and 1.5/100 person years for women. This population is largely young, female, and at considerable HIV risk. If follow-up could be improved, factory workers in northern Thailand could be an appropriate population in which to mount HIV preventive efficacy studies, including vaccine trials.

Measuring HIV-1 incidence in northern Thailand: prospective cohort results and estimates based on early diagnostic tests.

Measuring the incidence of the human immunodeficiency virus (HIV) is of vital importance but can be difficult and costly. We compared HIV-1 incidence measured directly from prospective cohort studies with rates derived from a method using the prevalence of HIV-1 antibody-negative, p24-antigen-positive individuals. Male and female commercial sex workers (CSWs) were enrolled and followed in separate cohort studies in northern Thailand between 1989 and 1994, and HIV incidence was measured by prospective follow-up of individuals seronegative at baseline. In 1991-1992 cross-sectional serosurveys were done among male and female CSWs in the same region; all HIV-1 antibody-negative subjects in these surveys were tested for p24 antigenemia. HIV incidence was estimated using the prevalence of p24 antigen and a model based on the mean duration of p24 antigenemia before HIV antibody detection. The cohort studies showed high initial incidence rates-23.8/100 person-years (PY) among female CSWs and 11.9/100 PY among male CSWs-but poor compliance with prospective follow-up. Subjects lost to follow-up appeared to be at greater risk of HIV seroconversion than those retained. The p24 antigen method estimate among female CSWs, 25.4%/year, was quite similar to the initial incidence rate found in the cohort. The estimate by the p24 antigen method was higher, 19.9%/year, among male CSWs than that measured prospectively. In populations with high rates of HIV transmission and in whom long-term follow-up is incomplete, estimates of incidence using p24 antigen prevalence among antibody-negative subjects can give useful and economical estimates of HIV incidence and allow for estimates of whether the incidence rates are similar in subjects successfully followed and those lost to follow-up.

Human immunodeficiency virus infection and self-treatment for sexually transmitted diseases among northern Thai men.

BACKGROUND AND OBJECTIVES: Self-treatment for sexually transmitted diseases (STD) is common, but little studied, in Thailand, and its influence on human immunodeficiency virus (HIV) infection is unknown. GOALS: To assess STD self-treatment and self-prophylaxis behaviors as well as HIV risks and serostatus among northern Thai men. STUDY DESIGN: Cross-sectional report from a cohort of military conscripts (N = 869). HIV and STD seroprevalence and reported risk behaviors, including STD history and antibiotic self-treatment, were obtained. Associations between STDs and self-treatment or prophylaxis and HIV infection were analyzed using t-tests, odds ratios, and logistic regression. RESULTS: The prevalence rate for HIV was 12.3%, and for syphilis it was 2.2%. Men who were seropositive for HIV were more likely to report having sex with commercial sex workers (OR 9.1), to have had an STD (OR 5.96) and to report inconsistent condom use with commercial sex workers (OR 3.13). Of 282 men reporting any STD, 65.2% treated themselves with antibiotics, and 8.5% used them before commercial sex. Among those who frequented commercial sex workers, 98.7% took preventive steps after sex by increasing urine output (69.2%), washing the genital area (28.9%), and using antibiotics (0.9%). Men reporting STD self-treatment were less likely to be HIV infected (OR 0.53; 95% CI 0.31, 0.93). CONCLUSIONS: These men are attempting to prevent HIV and STDs. Self-treatment with antibiotics may lower HIV risks associated with bacterial STD in a high-prevalence population.

PIP: In May 1993, at 11 military camps in the upper northern region of Thailand, civilians interviewed 869 men aged 21-29 years (most of whom were 21 years old) so researchers could determine the frequency and variety of self-treatment and self-prophylaxis behaviors for sexually transmitted disease (STD) and the relationship of these behaviors with the prevalence of HIV infection. 12.3% of the men at conscription into the military tested positive for HIV infection. 32.5% had ever had an STD. The leading STDs and syndromes were gonorrhea (16.1%), penile discharge with pus (15.5%), and pain while urinating (11.4%). HIV-positive men were more likely to have had sex with commercial sex workers (CSWs) (odds ratio [OR] = 9.14), to have had an STD (OR = 5.96), and not to use condoms consistently when having sexual intercourse with CSWs (OR = 3.13). 65.2% of men who had ever had an STD self-treated with antibiotics. 8.5% of men who had ever had an STD used antibiotics, particularly chloramphenicol, before having intercourse with a CSW. Among all the men who had sexual intercourse with CSWs, almost all (98.7%) had adopted steps to prevent STDs: increasing urine output (69.2%), washing the genitals with soap and water (28.9%), and using antibiotics (0.9%). Men who self-treated with antibiotics after having intercourse with CSWs were less likely to have HIV infection (OR = 0.53). Antibiotic use before intercourse with CSWs did not have as strong a protective effect as it did after intercourse (OR = 0.74). The protective effect of self-treatment was significant, even when controlling for syphilis, gonorrhea, lymphadenopathy, penile discharge with pus, and condom use with a CSW. These findings show that some sexually active men in northern Thailand are trying to prevent HIV and other STDs and that self-treatment with antibiotics may reduce the HIV risk associated with bacterial STDs in a high prevalence population.

Sequences and phylogenetic analysis of the nef gene from Thai subjects harboring subtype E HIV-1.

PIP: It has been demonstrated that nef-defective SIV can cause attenuated disease in rhesus monkeys and that animals immunized with a similar construct can be protected when challenged with wild-type, pathogenic SIV. This finding has sparked interest in the nef gene of HIV-1. It remains unclear, however, whether nef serves an analogous role in human HIV-1 infection; Deacon et al. have reported an association of deletions in the nef gene with an attenuated disease course in humans, although other work does not support a strict correlation between the structure or function of nef and rates of disease progression. The nef gene product has been shown to influence the infectivity and pathogenicity of HIV-1. nef may also have a role in the immune response to HIV-1. The current database of nef sequences is derived almost exclusively from subtype B viruses. The authors therefore sought to develop a database of nef sequences from subjects infected with HIV-1 subtype E. Whole-blood samples were collected from 103 male commercial sex workers in Chiang Mai, Thailand. 17 tested positive for infection with HIV-1, 16 of whom were infected with subtype E by gp120 characterization. Intersubject variation in subtype E nef genes at the nucleotide level ranged from 2.1-7.8%. Thai subtype E nef sequences are more tightly clustered than subtype B nef sequences, analogous to what is seen in env. The authors note that their subtype E nef sequences do not share the genotypic polymorphism in the area of residues 10-30 noted with subtype B nef. These data confirm the need to develop a set of subtype E-specific reagents.^ieng

Hepatitis B immunization: a potential incentive to HIV vaccine trial participation in Thailand?

To assess the effectiveness of hepatitis B immunization as an incentive to retention in HIV seroincidence studies and future HIV vaccine trials in northern Thailand, subjects enrolled in three HIV seroincidence cohorts were screened for hepatitis B markers and seronegatives were offered free hepatitis B immunization. Cohorts studied included female commercial sex workers (CSWs), male sexually transmitted disease (STD) patients, and recently discharged military conscripts. Subjects who agreed to the immunization program were compared with those not enrolled to determine the utility of immunization as an incentive to cohort retention. Full immunization was achieved for 273 (89.5%) of 305 vaccinees; only 323 (60.6%) of 533 subjects not immunized completed the same follow-up visits (OR = 1.49, 95% and CI = 1.27, 1.75). Hepatitis B vaccination was a significant incentive for completion of the follow-up program. The vaccination program had the greatest effect on the CSWs; a similar effect was seen for male STD patients, but not for discharged conscripts. Despite the immunization program, follow-up rates at 12 months were similar in the immunized and nonimmunized groups.

Willingness to participate in AIDS vaccine trials among high-risk populations in northern Thailand.

OBJECTIVES: To determine the anticipated participation in a prophylactic AIDS vaccine trial and to identify perceived benefits and barriers to enrollment of HIV-seronegative volunteers at risk of HIV infection in northern Thailand. DESIGN: A cross-sectional survey. METHODS: Subjects interviewed in a cross-sectional survey included female commercial sex workers (n = 215), men attending sexually transmitted disease clinics (n = 219), conscripts in the Royal Thai Army (n = 1453), and men discharged from the army (n = 293) who had returned to civilian life. We determined AIDS vaccine knowledge and attitudes, perceived vulnerability to HIV infection, barriers and incentives to participate in a future vaccine trial and agreement to participate in a randomized trial. RESULTS: Awareness of vaccines (88-97%) and AIDS vaccine development efforts (62-77%) were common and viewed to be a complement to behavior change (74-94%). Approximately 25% of subjects would definitely join a trial if asked, and an additional 38% would accept an AIDS vaccine if they were convinced it would be safe and effective. Important barriers to participation included concerns with discrimination (16-45%), short- (37-60%) and long-term (30-55%) vaccine side-effects, fear of disability and death (36-58%), and beliefs that partners would refuse to have sex (24-49%) after immunization. The principal inducement to join a trial was health insurance (62%). CONCLUSION: Potential HIV vaccine trial participants have several fears of joining a vaccine study at this time. Information derived from Phase I/II trials is needed to address these concerns if enrollment in efficacy trials is to be successful in the near future.

PIP: Thailand has been designated a site for preventive human immunodeficiency virus (HIV) vaccine trials, and Phase I and II trials are currently underway. To assess the feasibility of large-scale Phase III trials involving high-risk individuals, questionnaires were administered to four cohorts of potential participants from North Thailand: 215 female commercial sex workers recruited from sexually transmitted disease (STD) clinics, 219 male STD clients from the same area, 1453 men conscripted into the Royal Thai Army in 1993, and 293 men discharged from the Army in 1993. Approximately 25% of members of each cohort indicated they would definitely join a prophylactic acquired immunodeficiency syndrome (AIDS) trial. The major barriers to participation were concerns about vaccine safety (61% of military cohorts and 32% of civilians) and fear of acquiring AIDS through vaccination (21%). Also expressed were concerns about social discrimination, immediate side effects, and rejection by sexual partner. Two-thirds of respondents indicated that provision of a five-year family health insurance plan would induce them to participate in a vaccine trial, while another 25% did not require any incentive. Overall, these findings indicate that steps must be taken to alleviate fears and misconceptions associated with HIV vaccines before Phase III is initiated.

The epidemiology of HIV and syphilis among male commercial sex workers in northern Thailand.

OBJECTIVE: To examine the prevalence and incidence of HIV and syphilis, and risk behaviors for these infections, among 1,172 male commercial sex workers (CSW) followed prospectively from 1989 to 1994 in Chiang Mai, northern Thailand. METHODS: Twice yearly visits were conducted by the Thai Ministry of Public Health at all cooperating gay bars and clubs (17 sites) in Chiang Mai City as part of a national HIV sentinel surveillance. Men and boys who agreed were followed prospectively. Sentinel visits included an interview, HIV pre-test counseling, HIV and syphilis serology, condom distribution, and referral for post-test counseling. Participation was voluntary, confidential, and individual HIV results were available only to participating subjects. A total of 219 CSW were seen at least twice, allowing for incidence estimates based on 100 person-years (PY). RESULTS: Median age of male CSW was 20 years. Median time of work as a CSW was 4 months. Most men (57.6%) described themselves as heterosexual. Median number of clients was 2.5 per week, and reported condom use with clients was low: 42% reported inconsistent or no condom use, while 58% reported always using condoms. Reactive Venereal Disease Research Laboratory results were 7.6%, overall, but showed a declining trend. HIV prevalence was 1.4% in June 1989, 13.9% in June 1990, and 20.1% in December 1993, and showed a significant increasing trend. There were 27 incident HIV infections in 227.3 PY of observation, for an overall incidence during the 4.5-year period of 11.9 per 100 PY (95% confidence interval, 7.42-16.38). CONCLUSION: Male CSW in northern Thailand are at high risk for HIV despite current prevention efforts. The majority are heterosexual, which may be an important epidemiologic link in the spread of HIV between male CSW users and heterosexual women in Thailand.

PIP: The first confirmed case of human immunodeficiency virus (HIV) infection in Thailand was that of a Thai male commercial sex worker (CSW) in 1985. Since that time, this disease has manifested itself among injecting drug users, female sex workers, and in the general heterosexual and homosexual population. This paper reports the findings of a 5-year Thai study in which 1172 male CSWs were studied at least once. The purpose of the study was to identify the prevalence, incidence, and risk behaviors of CSWs regarding HIV and syphilis. The HIV prevalence increased from 1.4% in 1989 to 20.1% by 1993. Overall, the HIV prevalence for the 5-year period was statistically significant at 16.6%. Syphilis for this same period was 7.6% HIV infections were confirmed using enzyme-linked immunosorbent assay (ELISA). Multivariate analysis was calculated using multiple logistic regression. All CSWs in this study were provided with HIV pre-test counseling, were subjected to HIV and syphilis serology, were given condoms, and were provided with a referral for post-test counseling. Of the 1172 men seen, 219 (18.6%) were seen more than once. 27 cases of HIV infection were confirmed in the latter group (12.3%). Heterosexual men were found to be at lower risk of contracting an HIV infection than homosexual men.

Preparatory studies for possible HIV vaccine trials in northern Thailand.

We studied several populations of human immunodeficiency virus (HIV)-seronegative individuals from northern Thailand who were believed to be at relatively high risk of HIV infection in order to assess their potential suitability for inclusion in a preventive HIV vaccine trial. Included were female commercial sex workers (CSWs), male sexually transmitted disease (STD) clinic patients, male conscripts into the Royal Thai Army (RTA), and men who were recently discharged from the army. We evaluated their HIV prevalence, their interest in study participation, their compliance with prospective follow-up, and their HIV incidence. Among 1068 female CSWs the baseline HIV prevalence was 38.3%; of 659 HIV seronegatives 395 (59.9%) agreed to enrollment in the study. Follow-up at 6-9 months was 73.2%; it was 58% in brothel-based CSWs and 85% in non-brothel-based CSWs. Overall HIV incidence in CSWs was 8.2 per 100 person-years; incidence was 29 per 100 person-years in brothel-based CSWs and 4 per 100 person-years in non-brothel-based CSWs. Among 1031 male STD clinic patients, baseline HIV prevalence was 15.9%, follow-up was successful in 98.1%, and HIV incidence was 4.0 per 100 person-years. Among four cohorts of RTA conscripts who entered the military in 1991 and 1993, baseline HIV prevalence has been about 12%, follow-up about 90%, and HIV incidence has varied from 1.2-3.2 per 100 person-years. Discharged RTA conscripts have had baseline HIV prevalence of about 13%, successful follow-up of 94%, and an HIV incidence of about 5 per 100 person-years.(ABSTRACT TRUNCATED AT 250 WORDS)