The epidemiology of HIV infection and AIDS in Thailand

Thailand's response to the HIV epidemic: yesterday, today, and tomorrow

Thailand's comprehensive national response to the HIV/AIDS epidemic has been extensively documented since the beginning of epidemic. Substantial progress in the fight against HIV/AIDS has been made because awareness of the problem was raised. Top-level political commitment and multisectoral strategies mobilized funds and human resources to implement the control program at all levels. Behavioral change resulting in increased condom use in brothels on a national scale rose from virtually nil to more than 95%. This was accompanied by a 90% reduction of the sexually transmitted disease rate. In parallel, the rate of new HIV infections dropped by 80%. Despite these achievements, there remains an urgent need to continue efforts to ensure universal and unfailing condom use. Further, Thailand needs to establish pragmatic innovative approaches to reduce transmission, especially among injection drug users, women, and youth, as well as to develop effective strategies for implementation of antiretroviral treatment. Further strategies also need to consider the changing cultural, social, and economic characteristics of the Thai populations.

Comparison of HIV infection risk behaviors among injection drug users from East and West Coast US cities

This study assessed whether behavioral differences explained higher human immunodeficiency virus (HIV) seroprevalence among injection drug users (IDUs) in three East Coast versus two West Coast cities in the United States. Sociodemographic, sexual, and injecting information were collected during semiannual face-to-face interviews. Baseline data from New York City; Baltimore, Maryland; and New Haven, Connecticut, were compared with data from Los Angeles, California, and San Jose, California. Among 1,528 East Coast and 1,149 West Coast participants, HIV sero-prevalence was 21.5% and 2.3%, respectively (odds ratio [OR] 11.9; 95% confidence interval [CI] 7.9-17.8). HIV risk behaviors were common among IDUs on both coasts, and several were more common among West Coast participants. Adjusting for potential risk factors, East (vs. West) Coast of residence remained highly associated with HIV status (adjusted OR 12.14; 95% CI 7.36-20.00). Differences in HIV sero-prevalence between East and West Coast cities did not reflect self-reported injection or sexual risk behavior differences. This suggests that other factors must be considered, such as the probability of having HIV-infected injection or sexual partners. Prevention efforts are needed on the West Coast to decrease HIV-associated risk behaviors among IDUs, and further efforts are also needed to reduce HIV incidence on the East Coast.

The changing molecular epidemiology of HIV type 1 among northern Thai drug users, 1999 to 2002

CRF01_AE and subtype B have dominated the HIV-1 epidemic in Thailand since 1989. We reported a new circulating recombinant form of HIV-1, CRF15_01B, as well as other unique CRF01_AE/B recombinants among prevalent HIV infections in Thailand. We sought to study this challenging molecular picture through assessment of subtypes among recent HIV-1 seroconverters in northern Thai drug users. A total of 847 HIV-1 seronegative drug users (342 IDU and 505 non-IDU) were enrolled, from 1999 to 2002, in a prospective study; 39 HIV-1 incident cases were identified and characteristics were collected. The overall HIV-1 incidence rate was 2.54/100PY, but it was 10.0/100PY among male IDU. HIV was strongly associated with injection history; 38 of 39 seroconverters gave a history of IDU. A near full-length genome of HIV-1 was recovered by PCR amplification and sequenced from peripheral mononuclear cell extracted DNA of 38 seroconverters. Phylogenetic analysis revealed that 33 (86.8%) were CRF01_AE and 5 (13.2%) were CRF01_AE/B recombinants. These recombinants had different structure but shared some common breakpoints, indicating an ongoing recombination process. Recombinant infection increased with year of sampling (0 to 57.1%). The molecular epidemiology of HIV-1 among drug users in northern Thailand has thus entered a new era. CRF01_AE remains predominant while pure subtype B is becoming rare, and now a substantial component of the epidemic. These findings support the need for CRF01_AE and subtype B components in clade-matched vaccine strategies for Thai phase III trials. Ongoing molecular surveillance of circulating HIV-1 strains is imperative for the evaluation of HIV vaccine efficacy.

Recruitment, screening and characteristics of injection drug users participating in the AIDSVAX B/E HIV vaccine trial, Bangkok, Thailand

OBJECTIVES

To describe recruitment, screening and baseline characteristics of injection drug users (IDU) participating in a phase III HIV vaccine (AIDSVAX B/E; VaxGen, USA) trial and to compare enrollment characteristics between trial participants and 1209 IDU from a 1995-1998 vaccine trial preparatory cohort for changes that might impact trial design assumptions.

METHODS

Enrollment for both studies was conducted at Bangkok narcotic treatment clinics, where a standardized questionnaire was administered on demographics, risk behavior and incarceration history over the previous 6 months.

RESULTS

During 1999-2000, 4943 IDU were screened for enrollment; successful sources of recruitment included clinic attendees (43.4%), an IDU referral program (20.4%) and preparatory cohort participants (14.7%). Of those screened, 1689 (34%) were HIV seropositive (HIV subtype B 23.6%; subtype E 76.4%). Of the 2545 enrolled, 93.4% were male. Compared with cohort IDU, trial IDU were younger (mean age: 28.8 versus 31.3 years), better educated (secondary level or higher: 67.2% versus 58.7%), and less likely to inject drugs daily (39.4% versus 90.4%); they were more likely to have been incarcerated (78.4% versus 65.7%), have recently injected stimulants (14.8% versus 5.8%) and tranquilizers (11.5% versus 2.3%), and obtained needles/syringes from a source other than a pharmacist (7.2% versus 3.9%) (all P < or = 0.003).

CONCLUSIONS

IDU at high risk for HIV have been successfully enrolled in the AIDSVAX B/E efficacy trial. Only minor epidemiologic differences were found at enrollment between trial and preparatory cohort IDU. The latter has proven critical in guiding trial design; results are expected in late 2003.

Epidemiology of HIV and sexually transmitted infections in Thailand

There are very few developing countries in the world where public policy has been effective in preventing the spread of HIV/AIDS on a national scale. Thailand is an exception, a massive program to control HIV has reduced visits to commercial sex workers by half, raised condom usage, decreased sexually transmitted infections dramatically, and achieved substantial reductions in new HIV infections. However, unless past efforts are sustained and new sources of infection are addressed, the striking achievements made in controlling the epidemic could be put at risk. There is a need in Thailand to continue strong HIV/AIDS prevention and education efforts in the future, as well as to provide treatment and care for those living with HIV/AIDS.

Fleeing the Fire: Transformation and Gendered Belonging in Thai HIV/AIDS Support Groups

By the turn of the millennium, HIV had infected nearly one million people in Thailand. A large number of support groups now exist throughout the country. These groups have emerged as the primary forum through which having HIV is negotiated and normalized in Thai society. This is done by allowing members to publicly refashion their sense of self and its appropriate place in the world. However, the moral and social space created by support groups is not without its own structuring principles. The discursive strategies that shape support groups are embedded within local moral economies and frameworks of meaning. Gender and social identity are significant factors that influence the benefits to be gained from belonging. To date, women markedly outnumber men in most groups, and many members regard masculinity as a constraining factor on male participation. Within support groups, unwillingness to join is considered one reason for the perception that men with HIV seem to die sooner than do women with HIV. Clinically true or not, this belief has major ramifications.

HIV prevention among drug users: an international perspective from Thailand

All too often in reviews of HIV prevention needs, the role of drugs is summarily dismissed, especially in contexts where the heterosexual epidemic is the primary mode of transmission. Substance use and abuse, particularly injection drug use, play a paramount role in maintaining the heterosexual spread of HIV, as well as in maintaining epidemics where heterosexual spread of the infection has come under control due to prolonged and concerted HIV prevention activities. This article presents several themes to place in the developing country context what we have learned about substance use-related HIV prevention and the special problems of HIV interventions. First, the article briefly examines the international production and trade routes of opium and heroin and their role in the HIV epidemic, as well as the importance of substance abuse in heterosexual epidemics. Second, it presents a case study of HIV control that has been internationally acclaimed as one of the few successes in achieving a meaningful reduction in heterosexually transmitted HIV--Thailand. The Thai response to the injection drug use HIV epidemic, however, has been muted, and its impact on future epidemic dynamics is evaluated. The article concludes with a discussion of existing research gaps concerning the role of drug use in HIV epidemics in the developing world, with Thailand as an example.

HIV/AIDS and Sexually-transmitted Infections in Thailand: Lessons Learned and Challenges Ahead

Thailand has been able to reduce the potential impact of HIV/AIDS epidemic with concerted and exemplary efforts. The annual number of new HIV infections in the year 2001 was 25,790, compared to 142,819 in 1991. The key factors that contributed to the success of the HIV/ AIDS programmes include effective political and financial commitment at the highest level, multi- sectoral involvement, systemic epidemiological surveillance, social and behavioral research, and the institution of result-oriented interventions.

Despite this progress, the country must continue to improve the prevention efforts to further reduce the incidence and alleviate the impact of the burden of those persons living with HIV/ AIDS. Some challenges are to maintain and strengthen national STD prevention and control programme, to initiate and strengthen effective prevention programme among injecting drug users, to ensure increase theaccess to medical care for HIV/AIDS patients includingAR Vdrugs, and to expand multi-sectoral partnership in the design, implementation and evaluation of HIV/ AIDS-related policies and programmes to promote research.

HIV type 1 incidence estimates by detection of recent infection from a cross-sectional sampling of injection drug users in Bangkok: use of the IgG capture BED enzyme immunoassay

Development of serologic tests to detect recent HIV-1 infection has generated worldwide interest in applying this approach to estimate incidence. We previously devised an IgG-capture BED-EIA (or BED-CEIA) that detects increasing levels of anti-HIV IgG following seroconversion to identify recent infection and to estimate incidence among persons infected with diverse HIV-1 subtypes worldwide. Injection drug users (IDUs; n = 1969) were screened in 1996 for participation in a prospective cohort study. Serum specimens from 594 IDUs were HIV-1 seropositive (30.2%) and were tested with the BED-CEIA. The proportion of recent infections and estimated incidence by different epidemiological risk factors were compared with incidence data measured from the prospective cohort. Of 594 HIV-1-seropositive specimens, 113 (19%) were identified as recent infections. Overall, the estimated annual incidence among persons screened was 17.3%/year (95% CI, 12.8-24.2%/year) compared with 9.0%/year (95% CI, 6.7-11.9%/year) measured from the prospective cohort during the same time period. Estimated incidence was higher among younger aged and unemployed IDUs as well as among those who injected more frequently, confirming previously reported risk factors from this prospective cohort. As persons screened from a cross-sectional sampling probably have higher risk for HIV than selected uninfected individuals who choose to participate and receive risk reduction counseling in a longitudinal cohort study, use of this or other serologic testing strategies to identify populations with high incidence (such as for HIV vaccine trials) may overestimate incidence measured from prospective cohorts.

A new circulating recombinant form, CRF15_01B, reinforces the linkage between IDU and heterosexual epidemics in Thailand

HIV-1 subtype B and CRF01_AE have been in circulation in Thailand and Southeast Asia for more than a decade. Initially separated by risk group, the two strains are increasingly intermixed, and two recombinant strains of essentially reciprocal structure have been recently reported. Here we identify additional CRF_01B recombinants and provide the evidence that HIV-1 strains now pass freely between the two high-risk populations. HIV isolates that showed discordance between CRF01_AE and subtype B in multi-region genotyping assays were selected for the study. They were drawn from 3 different cohorts in Thailand representing different risk behaviors and demographic characteristics: a drug user cohort in the north, a family planning clinic attendee cohort in the southeast, and a cohort study of the mucosal virology and immunology of HIV-1 infection in Thailand. The DNA from these isolates was PCR amplified to recover the full HIV-1 genome and subjected to sequencing and phylogenetic analysis. We establish that one particular CRF_01B recombinant, with the external envelope of subtype B and the rest of the genome from CRF01_AE, is circulating widely in Thailand. Termed CRF15_01B (also referred to as CRF15), the strain was primarily heterosexually transmitted, although injecting drug use (IDU) also played a role. In aggregate data from the studies, CRF15 constituted 1.7% of all HIV-1 infections (95% confidence interval 0.5-4.4%) and was dispersed widely in the country. The previously separate heterosexual and IDU epidemics have apparently been bridged by a new CRF. The entry of CRF15 into the mainstream of the epidemic signals new complexity in the long stable molecular picture in Thailand. These recombinants must be considered in ongoing or projected efficacy evaluations of HIV-1 vaccines and antiviral therapies.

Temporal trends in the prevalence of HIV and other transfusion-transmissible infections among blood donors in northern Thailand, 1990 through 2001

BACKGROUND

Thailand's epidemic of HIV infection, which began in 1988, has primarily involved heterosexual transmission of the virus. This study describes changes in prevalence of HIV and other infectious diseases among blood donors in northern Thailand from 1990 through 2001.

STUDY DESIGN AND METHODS

Serologic screening results and demographic data were analyzed from 276,066 donors screened at two blood collection facilities in Chiang Mai, Thailand, from 1990 through 2001.

RESULTS

The HIV prevalence peaked in 1991 to 1993 at 4.04 percent and then declined to 0.38 percent in 2001. The overall prevalence of HIV infection was 2.16 percent; HIV prevalence was higher among male (2.24%) than among female (0.64%) donors, in first-time donors, and in replacement volunteer donors. The majority of the donors were men and first-time donors throughout this study. The prevalence of antibodies to syphilis decreased significantly in both men and women. However, the prevalence of antibodies to HCV and HBsAg were stable.

CONCLUSIONS

The declining HIV prevalence from 1990 through 2001 among blood donors in two large blood banks in northern Thailand indicates significant progress toward recruitment of a safer donor population in a developing country despite a major HIV and AIDS epidemic involving the general population.

HIV prevalence and risks among injection and noninjection drug users in northern Thailand: need for comprehensive HIV prevention programs

The authors sought to determine sociodemographic and sexual and drug use risk factors for HIV infection among drug users in northern Thailand adjacent to the Golden Triangle. The authors enrolled patients admitted for inpatient drug detoxification at one treatment center in northern Thailand and studied HIV risks and prevalence using an interviewer-administered questionnaire and serum collection with HIV pretest and posttest counseling. Between February 1, 1999 and January 31, 2000, 1865 patients admitted for opiate and methamphetamine dependence completed study procedures. Overall HIV prevalence was 10.3%: 30.0% among 513 injection drug users (IDUs) and 2.8% among non-IDUs (OR = 14.8, 95% CI: 10.2, 21.6). HIV seroprevalence was 2.4% among exclusive methamphetamine users (98% of whom are non-IDUs) and 3.4% among opium smokers. Injection drug use was the dominant risk factor in multivariate models. Although Thailand is widely recognized as having a successful national response to the heterosexual HIV epidemic, seroprevalence in IDUs remains high. Despite a sharp increase of non-IDUs admitted to the drug treatment center, HIV infection and risks remained high among IDUs in northern Thailand. HIV prevention campaigns need to focus on IDUs and to implement harm reduction strategies to reduce transmission to IDUs and further contain the HIV epidemic in Thailand.

AIDS and public policy: the lessons and challenges of "success" in Thailand

Thailand's public policy on AIDS is widely cited as one of the few examples of an effective national AIDS prevention program anywhere in the world. The Thai experience shows that a national response that mobilized key government and NGO partners and targeted the highest-risk transmission can be effective in reducing the scope of the epidemic, even when action is delayed. Based on interviews with policymakers, AIDS program managers, technical specialists, donors, and NGOs and on a review of the data, we highlight the lessons from public policy on AIDS in Thailand for other developing countries, review the state of the Thai epidemic and public policy in 2000, and identify three strategic priorities for the next phase of the response.

Sex-related health risks and implications for interventions with hospitality women in Hainan, China

This article describes the living situations of sex workers (hospitality girls) in a typical rural town in southern China; their personal, social, financial, and psychological needs and expectations; and the social and economic factors that place them at risk for STIs/HIV and unwanted pregnancy, based on the qualitative and quantitative data collected prior to and during a preventive intervention. Though some similarities to knowledge, attitudes, and behaviors of sex workers reported in other Asian countries were identified, this study identified some differences distinctive to the China context, such as how economic factors, kinship, and friendship networks function in the service industry, and how the culture of reproduction and birth control policy interact with and affect sex workers' health and decision-making options. Understanding these factors is critical for design of a culturally and contextually tailored intervention for the reduction of sex-related health risks of women in the sex service industry.

Survival benefit from non-highly active antiretroviral therapy in a resource-constrained setting

Mortality rates among HIV-1-infected patients attending a government hospital in northern Thailand were investigated to evaluate the effect of antiretroviral (ARV) drug therapy on mortality. Demographic, clinical, and laboratory data and history of ARV drug therapy were collected from all HIV-1-infected adult patients who attended the Day Care Center clinic from October 2, 1995 through October 31, 1999. The survival status of patients until October 31, 1999 was ascertained from the hospital records, mailing letters, and death certificates at the Provincial Health Office. Of 1110 patients who attended the clinic, we had data on duration of follow-up for 1081 (97%) with a total of 1175 person-years of observation; 607 (54.7%) patients died. Clinical status, CD4 group, ARV drug group, and registered year were independently associated with death. The adjusted hazard ratio of monotherapy to no therapy was 0.65 (95% CI: 0.48, 0.87; p = .001) and that of dual therapy was 0.43 (95% CI: 0.29, 0.62; p < .001). The mortality rate of patients attending a government hospital in northern Thailand is high. Suboptimum ARV drug regimens like dual therapy had a substantial survival benefit. Further cost reduction for multiple ARV drug regimens is impatiently awaited.

Resourcefulness and self-care in pregnant women with HIV

The human immunodeficiency virus (HIV) has caused suffering in the lives of humans worldwide. Pregnant Thai women now constitute the fastest-growing segment of individuals diagnosed with HIV/AIDS. Few studies have looked at self-care or resourcefulness among pregnant women with HIV. Using Rosenbaum's theory of learned resourcefulness, this study examined the direct effects of depression and resourcefulness on prenatal self-care as well as the mediating effects of resourcefulness on depression and self-care. A model testing study with 153 pregnant Thai women compared the effects of depression and resourcefulness on prenatal self-care in HIV-positive and HIV-negative groups. Regression analyses indicated direct effects of depression and resourcefulness on prenatal self-care. The effect of depression on prenatal self-care was mediated by resourcefulness. HIV status did not predict prenatal self-care. The findings on the relationships of depression, resourcefulness, and prenatal self-care can help nurses provide effective services to pregnant Thai women, including counseling on self-care.

The sequential introduction of HIV-1 subtype B and CRF01AE in Singapore by sexual transmission: accelerated V3 region evolution in a subpopulation of Asian CRF01 viruses

The rapid spread of the human immunodeficiency virus type 1 (HIV-1) circulating recombinant form (CRF) 01AE throughout Asia demonstrates the dynamic nature of emerging epidemics. To further characterize the dissemination of these strains regionally, we sequenced 58 strains from Singapore and found that subtype B and CRF01 were introduced separately, by homosexual and heterosexual transmission, respectively. Protein similarity scores of the Singapore CRF01, as well as all Asian strains, demonstrated a complex distribution of scores in the V3 loop--some strains had very similar V3 loop sequences, while others were highly divergent. Furthermore, we found a strong correlation between the loss of a V3 glycosylation site and the divergent strains. This suggests that loss of this glycosylation site may make the V3 loop more susceptible to immune surveillance. The identification of a rapidly evolving population of CRF01AE variants should be considered when designing new candidate vaccines and when evaluating breakthrough strains from current vaccine trials.

The evolving epidemiology of HIV infection and tuberculosis in northern Thailand

OBJECTIVES

To examine the association between HIV infection and tuberculosis (TB) and the proportion of TB attributable to HIV in Chiang Rai province, northern Thailand, in response to a rapidly changing incidence of HIV infection.

METHODS

Case-control study covering the period 1990 to 1998. Cases were all new TB patients seen at Chiang Rai Hospital. Controls were antenatal clinic attendees, delivery patients, surgical patients, blood donors, and military conscripts. Odds ratios (ORs) were calculated by year, age group, and sex, using each control group separately. The population attributable fraction was calculated by year.

RESULTS

During the study period, the number of new TB cases in Chiang Rai Hospital increased more than threefold. The ORs increased over time compared with all control groups for both sexes but did not vary consistently with age. The proportion of TB cases attributable to HIV rose to 72.0% in male patients and 65.8% in female patients by 1998.

CONCLUSIONS

The HIV epidemic has a profound and prolonged impact on TB burden. Despite the marked reduction in HIV incidence already seen in Chiang Rai, the HIV prevalence among TB cases and the proportion of cases attributable to HIV continue to rise.

Higher viral loads and other risk factors associated with HIV-1 seroconversion during a period of high incidence among injection drug users in Bangkok

We analyzed data from a prospective cohort study of injection drug users (IDUs) attending methadone treatment clinics in Bangkok, Thailand, during 1995-1998 to characterize factors associated with a period of high incidence (PHI) from July 1996 through January 1997 compared with periods of lower incidence. Sociobehavioral characteristics were similar for all participants during and outside the PHI except for the following: there was more reported drug injection while IDUs were incarcerated during the PHI (odds ratio, 1.67; p =.02) and significantly higher proportions of persons reported heroin injection (91% vs. 75%, respectively; p =.02) and higher frequencies of daily injection and sharing of injection equipment (40% vs. 25%, respectively; p =.05) during the PHI than outside the PHI. Through most of the first year after seroconversion, plasma HIV-1 loads were significantly higher in persons who seroconverted during the PHI than in those who seroconverted outside the PHI. Higher viral loads may potentially contribute to faster disease progression and increased infectiousness or transmissibility to subsequent contacts. Our findings suggest that prevention efforts to reduce the effective size and turnover within IDU sharing networks may have a significant impact on the epidemic by disrupting the rapid transmission of HIV-1 from recently infected, highly infectious individuals.

Genetic analysis of incident HIV-1 strains among injection drug users in Bangkok: evidence for multiple transmission clusters during a period of high incidence

During 1995-1996, 1,209 HIV-1-negative injection drug users (IDUs) attending methadone treatment clinics operated by the Bangkok Metropolitan Administration in Bangkok, Thailand, were enrolled in a prospective cohort study. Through 1998, 133 of these IDUs had seroconverted to HIV-1; 130 of these seroconverters were included in this study. HIV-1 CRF01_AE and subtype B strains accounted for 79% and 21% of the incident infections, respectively. To examine phylogenetic relationships among these incident HIV-1 strains, we used several phylogenetic inference methodologies to analyze the env (C2-V4) sequences in blood samples collected soon after seroconversion. These analyses consistently revealed eight phylogenetic clusters comprising 21 incident strains (bootstrap method, >80%; six CRF01_AE and two subtype B clusters). Two factors were found to be associated with the eight clusters. The first factor was temporal: seven of the eight clusters comprised 17 sequences from IDUs whose estimated dates of seroconversion were within a period of high incidence from July 1996 through January 1997. The second factor was a possible geographic association: four clusters were observed among IDUs who had attended the same methadone treatment clinics. These phylogenetic clusters likely represent subgroups within larger HIV transmission networks among IDUs in Bangkok. Despite prevention efforts, the incidence of HIV-1 infection among the Bangkok IDU population continues to be high. A better understanding of transmission networks and factors associated with such networks can help guide prevention efforts.

Comprehensive screening for human immunodeficiency virus type 1 subtype-specific CD8 cytotoxic T lymphocytes and definition of degenerate epitopes restricted by HLA-A0207 and -C(W)0304 alleles

For this report, the rapid identification and characterization of human immunodeficiency virus type 1 (HIV-1)-derived broadly cross-subtype-reactive CD8 cytotoxic T lymphocyte (CTL) epitopes were performed. Using a gamma interferon (IFN-gamma) Elispot assay-based approach and a panel of recombinant vaccinia viruses expressing gag, env, pol, and nef genes representing the seven most predominant subtypes and one circulating recombinant form of HIV-1, the subtype specificity and cross-subtype reactivity of a CD8 response were directly measured from circulating peripheral blood mononuclear cells (PBMC). Enhanced sensitivity of detection of CD8 responses from cryopreserved PBMC was achieved using autologous vaccinia virus-infected B-lymphoblastoid cell lines as supplemental antigen-presenting cells. Of eleven subjects studied, six exhibited broadly cross-subtype-reactive CD8-mediated IFN-gamma production (at least seven of eight subtypes recognized) to at least one major gene product from HIV-1. Screening of subjects showing broadly cross-subtype-specific responses in the vaccinia virus-based enzyme-linked immunospot (Elispot) assay using a panel of overlapping peptides resulted in the identification of cross-subtype responses down to the 20-mer peptide level in less than 3 days. Three subjects showed broad cross-subtype reactivity in both the IFN-gamma Elispot assay and the standard chromium release cytotoxicity assay. Fine mapping and HLA restriction analysis of the response from three subjects demonstrated that this technique can be used to define epitopes restricted by HLA-A, -B, and -C alleles. In addition, the ability of all three epitopes to be processed from multiple subtypes of their parent proteins and presented in the context of HLA class I molecules following de novo synthesis is shown. While all three minimal epitopes mapped here had previously been defined as HIV-1 epitopes, two are shown to have novel HLA restriction alleles and therefore exhibit degenerate HLA binding capacity. These findings provide biological validation of HLA supertypes in HIV-1 CTL recognition and support earlier studies of cross-subtype CTL responses during HIV-1 infection.

Acceptance of HIV testing and counseling among unmarried young adults in Northern Thailand

A cluster randomized trial was used to assess the effect of an active group intervention in promoting utilization of voluntary HIV testing and counseling (HIV-TC). Villagers from 40 clusters were sampled to represent the premarital age population and assigned into two groups, intervention and comparison. The intervention was designed to enhance risk perception and increase knowledge about HIV testing. Interviews were performed before and after the intervention. At baseline, 23% of 398 participants had been tested for HIV at least once and 90% reported testing positive. Most participants perceived that they had no chance of being infected with HIV. Among the intervention group, 71% participated in the intervention activities. The risk ratio of HIV-TC acceptance among the intervention group was 2.92, but the risk difference was only 8.11%. Factors associated with HIV-TC acceptance were ever having had a sexually transmitted disease, being previously married, intention to get tested, and having partici pated in AIDS-related activities.

Incidence of HIV-1 infection and effects of clinic-based counseling on HIV preventive behaviors among married women in northern Thailand

To determine the incidence of and risk factors for HIV-1 infection among married women in northern Thailand, we enrolled 779 seronegative women from family planning clinics and a postpartum ward in Chiang Rai, Thailand, from 1998 through 1999. Women were tested for HIV antibodies at 6 and 12 months after enrollment. They received HIV prevention counseling at enrollment and at each follow-up visit. Counseling covered partner communication, partner HIV testing, and condom use by steady partners. Effects of counseling were measured using standardized questionnaires. Follow-up rates were 94% at 6 months and 92% at 12 months. Only 1 woman seroconverted during the follow-up period, yielding an overall HIV incidence of 0.14 per 100 person-years. After receiving counseling, women reported significantly increased communication with husbands concerning HIV risk, HIV testing, and condom use during the first 6 months after enrollment; communication remained high for 6 to 12 months. Women reported a modest increase in HIV testing and consistent condom use by husbands. The risk for HIV transmission to women in steady relationships is low in northern Thailand. Although HIV prevention counseling promoted partner communication, its effects on HIV preventive behaviors were limited.

The global tuberculosis situation. Progress and problems in the 20th century, prospects for the 21st century

Mycobacterium tuberculosis has been identified in prehistoric remains of humans. Despite references to TB by Hippocrates and Galen, humankind had limited understanding of and few tools to defend itself against TB until the later 19th century. Subsequently, landmark advances in the 20th century provided the means to control and prevent this disease. At the same time, epidemiological developments and fundamental problems related to human behavior, socioeconomic conditions, and political circumstances continue to thwart efforts to diminish the burden of suffering and death caused by TB. This article reviewed some of these issues including the global failure of TB control in the late 20th century, the worldwide emergence of drug-resistant TB, the extensive spread of HIV infection and its impact on TB incidence; and changing health care and political environments. The obstacles to TB control remain and will remain challenges in the coming years. Still, recent developments in immunology, biochemistry, and molecular biology suggest that new knowledge and tools are just around the corner. These will enhance the ability to conquer this microbe by the end of the current century.

Isolation and characterization of replication-competent molecular DNA clones of HIV type 1 CRF01_AE with different coreceptor usages

We have isolated replication-competent molecular clones of HIV-1 circulating recombinant form CRF01_AE with different coreceptor usages. After lambda phage cloning of unintegrated circular proviral DNAs derived from a CRF01_AE strain (HIV-1NH1), isolated in Japan, the infectious molecular clone, designated p93JP-NH1, was reconstituted. 93JP-NH1 showed an X4 and R5 phenotype in NP2 cell-based coreceptor utilization assays and exerted robust replication in human T cell lines, including MT2, M8166, and PM1 cells, whereas it propagated modestly in peripheral blood mononuclear cells. The CRF01_AE molecular clone with R5 phenotype (p93JP-NH2env) was then constructed by replacing the env gene of p93JP-NH1 with that of a nearly isogenic CRF01_AE R5 strain isolated from an epidemiologically linked case. The phylogeny and recombination break-point analysis confirmed that these clones shared an A/E recombinant structure similar to that of the prototype CRF01_AE strain, CM240. These replication-competent CRF01_AE molecular clones with different coreceptor usages would be useful tools for the study of CRF01_AE, one of the most prevalent strains in Asia.

Risk factors of HIV infection and needle sharing among injecting drug users in Ho Chi Minh City, Vietnam

OBJECTIVE

We sought to identify risk factors for needle sharing and HIV infection among injecting drug users (IDUs) in Ho Chi Minh City (HCMC), Vietnam.

METHODS

Three cross-sectional surveys among IDUs, both on the street (in 11 urban districts) and in the rehabilitation center for IDUs in HCMC, were carried out in April of 1995, 1997, and 1998. Outreach workers interviewed IDUs about socio-demographic characteristics, drug use and sexual practices, and HIV knowledge and perceptions. The IDUs were also tested for seropositivity to HIV. Independent predictors for HIV positivity and needle sharing were determined by univariate and multivariate logistic regression for the study sample within the rehabilitation center in 1997 and for that on the street in 1998.

RESULTS

The HIV prevalence in 1998 among IDUs was 44% for those on the street and 38.5% for those in the rehabilitation center. Independent predictors for HIV infection in IDUs were being injected by drug dealers (for the 1997 sample), injecting on the street, and sharing the drug pots (for the 1998 sample). The reported rate of needle sharing was low and decreased significantly from 20% in 1995 to 12% in 1998 for the sample of IDUs at the street. In the multivariate analysis, predictors for needle sharing for both study samples were injecting on the street, injecting at shooting galleries, and having shared needles in the past. Adequate and easy access to sterile needles and syringes, and a supportive environment of behavior change, especially in street and shooting gallery could reduce risks of virus transmission in the Vietnamese IDU community.

HIV infection in young men in northern Thailand, 1991-1998: increasing role of injection drug use

Epidemic HIV-1 infections were first recognized in Thailand in 1988 but increased dramatically in the 1990s primarily as a result of sexual transmission. The Ministry of Public Health instituted programs, including condom promotion during commercial sex, and health education to prevent HIV transmission. We assessed the HIV infection prevalence and risk behaviors among eight cohorts of 21-year-old randomly selected male military conscripts in northern Thailand between 1991 and 1998 to evaluate temporal trends in HIV infection and risk behavior. The prevalence of HIV was 11.4% to 11.9% in 1991 through 1993 and progressively fell to 2.4% in 1998. The men reported progressive decreases in commercial sex from 80% in 1991 to 38% in 1998, increases in condom use for commercial sex to greater than 95% in 1998, and decreases in lifetime history of a sexually transmitted infection from 42% in 1991 to 4.4% in 1997. There was an increasing proportion of men who reported a history of injecting illicit drugs, however, which involved 1.0% of the men in 1991 but 4.2% in 1997. The population attributable risk of drug use for HIV infection increased in recent years; the proportion of HIV-positive men with a history of drug use increased from 1.0% in 1991 to 25.8% in 1998. The public health program to prevent the sexual transmission of HIV in Thailand continues to be highly successful. Nevertheless, injection drug use has emerged as an important risk behavior and is maintaining endemic HIV transmission in Thailand.

Shan women and girls and the sex industry in Southeast Asia; political causes and human rights implications

The human rights abuses which occur during civil conflicts pose special threats to the health and lives of women. These can include rape, sexual violence, increased vulnerability to trafficking into prostitution, and exposure to HIV infection. The long-standing civil conflict in the Shan States of Burma is investigated as a contributing cause to the trafficking of ethnic Shan women and girls into the Southeast Asian sex industry, and to the subsequent high rates of HIV infection found among these women. The context of chronic human rights abuses in the Shan states is explored, as well as the effects of recent forced population transfers on the part of the Burmese Military Regime. Rights abuses specific to trafficked women may further increase their vulnerability to HIV and other STD. The need for a political resolution to the crisis in Burma is discussed, as are approaches aimed at preventing trafficking, empowering women already in the sex industry, and reducing the risks of HIV and other STD among these women and girls.

Full-length sequences of two CRF01_ae (subtype e) HIV type 1 isolates from 1995 samples of patients with sexually transmitted diseases in Thailand

We isolated two CRF01_AE human immunodeficiency virus type 1 (95TNIH022 and 95TNIH047) from the 1995 blood samples derived from asymptomatic carriers in Ubonratchatani province of northeastern Thailand. Both isolates can replicate in peripheral blood mononuclear cells, but not in several T cell lines examined. The full-length sequences recovered from proviruses in infected cells by long-range polymerase chain reaction were determined. Phylogenetic analyses of these sequences at individual genes showed them to be closely related to those of reported CRF01_AE HIV-1, such as 1990 isolate CM240 and 1993 isolate 93TH253. Two isolates in this study also showed a similar pattern of CRF01_AE mosaicism and a similar structure at the long terminal repeat, i.e., a copy number of NF-kappaB binding sites, sequence at the TATA box, and the putative secondary structure of stem-loop in the transactivation response region. Our results showed that 1995 Thai E isolates could contribute to our understanding of the epidemiology, pathogenesis, and diagnostics of HIV-1 CRF01_AE and further to vaccine development.

An HLA-directed molecular and bioinformatics approach identifies new HLA-A11 HIV-1 subtype E cytotoxic T lymphocyte epitopes in HIV-1-infected Thais

Only limited cytotoxic T lymphocyte (CTL) epitope mapping has been done in nonsubtype B HIV-infected persons. We used molecular immunogenetic tools to determine HIV-specific CTL responses in HIV-1 Env subtype E-infected female sex workers (FSWs) from northern Thailand, where more than 50% of the population is HLA-A11 positive. EpiMatrix, a computer-based T cell epitope prediction algorithm, and a manual editing approach were used to predict 77 possible HLA-A11 CTL epitopes in HIV-1, some of which were conserved between subtypes B and E. MHC binding of these peptides was determined in an HLA-A11 stabilization assay, and binding peptides were tested for CTL recognition in eight HLA-A11-positive FSWs. Subtype E versions of known HLA-A2 subtype B HIV epitopes were also tested in four HLA-A2 positive FSWs. CTL responses were detected in all HLA-A11-positive and in three of four HLA-A2-positive persons. Among the 12 FSWs responses to peptides were found to Pol in 9 (75%), Env in 7 (58%), Nef in 5 (42%), and Gag in 5 (42%), and to conserved epitopes in 8 (67%). To identify HLA-A11 CTL epitopes in the absence of prediction tools, it would have been necessary to test almost 3000 10-mer peptides. EpiMatrix and manual predictions reduced this number to 77, of which 26 were MHC binding and 12 were CTL epitopes. Six of these HLA-A11 CTL epitopes have not been previously reported and are located in RT, gp120, and gp41. This report of CTL responses in subtype E-infected individuals defines epitopes that may be useful in HIV pathogenesis or vaccine studies.

Viral load differences in early infection with two HIV-1 subtypes

OBJECTIVES

Information on early HIV-1 infection has come primarily from studies of persons infected with subtype B in North America and Europe; much less is known about other subtypes. The purpose of the present study was to compare the virologic and immunologic parameters following seroconversion among recently-infected persons infected with either of two different HIV-1 subtypes.

METHOD

A prospective cohort study was carried out at methadone treatment clinics administered by the Bangkok Metropolitan Administration, Thailand. A total of 130 HIV-1-infected seroconverters (103 with HIV-1 subtype E and 27 with subtype B) were included in the study. The main outcome measures were serial HIV-1 RNA viral load, natural killer cell percentage, CD4 and CD8 lymphocyte counts since seroconversion.

RESULTS

The demographic and behavioral characteristics of persons with either subtype were similar. Median RNA viral levels at the earliest time within 3 months of seroconversion were more than three times higher for persons infected with subtype E than subtype B (63 100 versus 18 050 copies/ml, P = 0.001). However, this difference decreased over time such that viral loads were similar at 12, 18, and 24 months following seroconversion. The CD4 and CD8 lymphocyte counts were similar in infections with either subtype during the entire period up to 24 months post-seroconversion.

CONCLUSIONS

Higher viral loads associated with subtype E may result from inter-subtype biological differences; however, the epidemiological dynamics of transmission in Bangkok may have also contributed to this phenomenon.

HIV viral load in Thai men and women with subtype E infections

The assessment of potential "breakthrough infections" in HIV vaccine trials requires knowledge of viral load in unvaccinated persons. Therefore, HIV-1 RNA was quantitated in plasma from Thai adults with subtype E infections. RNA was detectable (> or =500 copies/ml) in 93% of 255 specimens, with a mean (standard deviation) value of 4.09 (0.88) log copies/ml. The concentration of RNA was directly related to the presence of AIDS-defining illnesses, inversely related to CD4 count, and independent of gender after adjustment for CD4 count.

Detection and quantification of HIV type 1 RNA in nasopharyngeal washes from HIV-infected subjects

Human immunodeficiency virus type 1 (HIV) RNA load was measured in paired samples of peripheral blood plasma and nasopharyngeal (NP) washes from 97 Thai subjects infected with subtype E or B. HIV RNA was quantifiable in 93% of peripheral blood plasma samples tested and was inversely correlated (rho =-0.524; p < 0.001) with CD4 absolute count. HIV RNA was quantifiable in 29% of NP samples tested, and the median value was less than that of plasma viral load. HIV RNA load in NP samples was correlated (rho = 0.388; p < 0.001) with viral load in peripheral blood. HIV RNA was not detected in NP washes from subjects with undetectable plasma viral load. Virus isolation attempts on two NP samples were negative. The results do not support local HIV production in the nasopharynx, but extend current knowledge of HIV shedding to include the NP compartment.

Reawakening the dragon: changing patterns of opiate use in Asia, with particular emphasis on China's Yunnan province

Asian countries adjacent to the Golden Triangle and their neighbors have witnessed an evolution in "drug abuse" from traditional opium smoking to heroin eating, smoking, and finally heroin injection. A recent study of 630 heroin users was conducted in China's Yunnan Province, located close to the Golden Triangle. Data collected between August 1997 and February 1998 indicate injecting heroin users, in comparison to noninjectors, were more likely to have used drugs for a longer period of time, and to use drugs more frequently everyday. Other major differences existed between urban and rural subjects, especially highlighting differences between men and women. Women comprised a much higher proportion of urban subjects than rural subjects. Rural injectors were much more likely to be male, but urban injectors were almost evenly split between men and women. The emerging epidemic of heroin use in China and the continuing substance abuse problem in the United States provide an opportunity for collaborative research of mutual benefit.

Thai Red Cross zidovudine donation program to prevent vertical transmission of HIV: the effect of the modified ACTG 076 regimen

OBJECTIVES

To evaluate the impact of the modified ACTG 076 zidovudine regimen on the risk for vertical HIV transmission.

DESIGN

Observational retrospective evaluation of a prospective cohort.

SETTING

Thai Red Cross zidovudine donation program to reduce vertical HIV transmission.

PATIENTS

HIV-infected Thai women and their offspring.

INTERVENTION

The modified regimen consisted of 500 mg zidovudine daily during pregnancy and 300 mg zidovudine every 3 h during labor, taken orally, and 2 mg/kg zidovudine syrup four times daily for 6 weeks to infants.

MAIN OUTCOME MEASURES

Only infants with at least 1 HIV DNA polymerase chain reaction (PCR) result at age > or = 4 weeks were included. HIV infection was defined by having at least one positive PCR at age > or = 4 weeks. The transmission rate was calculated. Characteristics of women who did and did not transmit HIV to infants were compared.

RESULTS

A total of 2891 women and their infants participated in the program and 726 infants of 719 women were included in the analysis. Forty-three infants were infected. The overall transmission rate was 6.0% (95% confidence interval, 4.4-8.0). There were no differences in maternal characteristics between transmitters and non-transmitters. The transmission rate in women who started zidovudine before 30 weeks' gestation was not significantly different from that in women who started zidovudine at or after 30 weeks' gestation: 5.7 versus 3.3%, respectively.

CONCLUSIONS

This modified zidovudine regimen is effective in reducing vertical transmission in a country with predominant subtype E infection. A donation program for preventing vertical HIV transmission can be implemented in developing countries, as in Thailand.

HIV-1 seroprevalence, risk factors, and preventive behaviors among women in northern Thailand

To study HIV-1 seroprevalence, risk factors, and preventive behaviors among reproductive-age women in northern Thailand, 804 consenting women who were identified postpartum or who were visiting family planning clinics were interviewed and tested during 1998 to 1999. Almost all women were currently married and had been pregnant more than once. Their median age was 27 years. HIV-1 seroprevalence was 3.1% overall and was higher in women aged between 25 and 29 years (5.9%), having had > or =2 lifetime sex partners (6.5%), or whose current marriage had lasted for < or =1 year (7.0%). No woman reported HIV risk factors other than heterosexual sex. Most (76%) HIV-infected women reported no casual sex partners and, therefore, had likely acquired the infection from their husbands. HIV testing and partner communications were common, but only 2% of couples used condoms consistently in the prior 6 months. Nearly half of these women perceived themselves at no or low risk for HIV infection; these women were less likely to have taken preventive actions. To prevent HIV transmission in stable partnerships in this population, additional efforts are needed to increase HIV testing and condom use, to improve women's negotiation skills, and to develop new methods that do not require partner cooperation such as vaginal microbicides or vaccines.

Explosive spread and effective control of human immunodeficiency virus in northernmost Thailand: the epidemic in Chiang Rai province, 1988-99

The human immunodeficiency virus type 1 (HIV-1) epidemic began in Asia later than most in other regions but then spread very rapidly. Upper northern Thailand was severely affected, with among the highest infection rates in Asia. The first 12 years of the HIV epidemic in Chiang Rai, Thailand's northernmost province are described. HIV infection was not reported in Chiang Rai until 1988 but, within a few years more than half of the brothel-based female sex workers and one in six of 21-year-old male Royal Thai Army conscripts from the province were HIV infected. Infection rates in Chiang Rai have since declined following an aggressive prevention campaign, but the number of AIDS cases continues to mount, along with profound demographic, social and economic effects.

Empirical Bayes approach to estimating the number of HIV-infected individuals in hidden and elusive populations

In this paper we estimate the numbers of intravenous drug users (IVDUs) and commercial sex workers (CSWs) in Thailand infected with human immunodeficiency virus (HIV) who have not developed acquired immunodeficiency syndrome (AIDS) directly from the semi-annual HIV serosurveillance data of Thailand from June 1993 to June 1995. We propose a 'generalized removal model for open populations' for estimating HIV-infected population size within a hidden, elusive, and perhaps high-risk population group, for all sampling time when capture probabilities vary with time. We apply empirical Bayes methodology to the generalized removal model for open populations by using the Gibbs sampler, a Markov chain Monte Carlo method. No assumption on the size of the hidden population in question is needed to implement this procedure. The statistical method proposed here requires very little computing and only a minimum of two sets of serosurvey data to obtain an estimate, thereby providing a simple and viable option in epidemiological studies when either powerful computing facilities or abundant sampling data are lacking.

Emerging genetic diversity of HIV-1 in South America

OBJECTIVE

Genotype determination and risk group analysis of HIV-1 infected individuals in selected regions of South America.

DESIGN

Cross-sectional convenience sampling of HIV-1-positive individuals in Peru, Ecuador, Uruguay and Paraguay from March, 1994 through September, 1998.

METHODS

HIV-1-positive subjects were identified through the national AIDS surveillance program in each country. A standardized questionnaire was used to obtain demographic, clinical and risk factor data on each study subject. Viral DNA was extracted from participants' peripheral blood mononuclear cells either directly or after co-cultivation. A nested PCR was used to obtain selected fragments of the envelope genes for genotyping by the heteroduplex mobility assay (HMA). A 600 bp sequence encompassing the V3 loop was sequenced from a selection of 23 of these samples for phylogenetic analysis and confirmation of HMA genotype.

RESULTS

Among the 257 successfully genotyped HIV-1-positive samples, genotype B was found in 98.3% (228/232) of those obtained from subjects in Peru, Ecuador, and Paraguay. In contrast, 56% (14/25) of the samples from Uruguay were genotype F, and the remainder were genotype B. Genotype F was detected for the first time in Peru (2/224) and Paraguay (1/4), and genotype A for the first time in Peru (1/224). Phylogenetic analysis confirmed the genotype identified by HMA in the 23 samples sequenced. There was no detectable genetic clustering of HIV-1 within the different high-risk groups or geographic locations.

CONCLUSIONS

These findings verify and extend the presence of several different HIV-1 genotypes in South America.

Determination of human immunodeficiency virus type 1 subtypes in Taiwan by vpu gene analysis

The genetic diversity of human immunodeficiency virus (HIV) type 1 (HIV-1) has been characterized mainly by analysis of the env and gag genes. Information on the vpu genes in the HIV sequence database is very limited. In the present study, the nucleotide sequences of the vpu genes were analyzed, and the genetic subtypes determined by analysis of the vpu gene were compared with those previously determined by analysis of the gag and env genes. The vpu genes were amplified by nested PCR of proviral DNA extracted from 363 HIV-1-infected individuals and were sequenced directly by use of the PCR products. HIV-1 subtypes were determined by sequence alignment and phylogenetic analysis with reference strains. The strains in all except one of the samples analyzed could be classified as subtype A, B, C, E, or G. The vpu subtype of one strain could not be determined. Of the strains analyzed, genetic subtypes of 247 (68.0%) were also determined by analysis of the env or gag gene. The genetic subtypes determined by vpu gene analysis were, in general, consistent with those determined by gag and/or env gene analysis except for those for two AG recombinant strains. All the strains that clustered with a Thailand subtype E strain in the vpu phylogenetic analyses were subtype E by env gene analysis and subtype A by gag gene analysis. In summary, our genetic typing revealed that subtype B strains, which constituted 73.8% of all strains analyzed, were most prevalent in Taiwan. While subtype E strains constituted about one-quarter of the viruses, they were prevalent at a higher proportion in the group infected by heterosexual transmission. Genetic analysis of vpu may provide an alternate method for determination of HIV-1 subtypes for most of the strains, excluding those in which intersubtype recombination has occurred.

AIDSVAX (MN) in Bangkok injecting drug users: a report on safety and immunogenicity, including macrophage-tropic virus neutralization

A randomized, double-blind, placebo-controlled phase I/II study of AIDSVAX (MN) was conducted among injecting drug users in Bangkok, Thailand. Four doses of vaccine (300 microg of MN-rgp120 in alum) or placebo (alum) were given at study entry and at 1, 6, and 12 months. The objectives of the study were to evaluate (1) the feasibility of conducting vaccine trials in this population; (2) the safety of this candidate AIDS vaccine; and (3) the immunogenicity of this vaccine. Thirty-three volunteers (22 vaccine and 11 placebo recipients) were recruited. None were lost to follow-up during the 18-month study. Mild reactogenicity was noted, which was similar in both vaccine and placebo recipients. The vaccine induced anti-HIV-1 antibody in all vaccine recipients. Maximal titers of binding antibodies of MN-rgp120 and the V3 domain of MN-rgp120 were induced after the third (6 month) dose while maximal neutralizing antibodies followed the fourth (12 month) dose. The vaccine-induced antibodies from several volunteers were capable of neutralizing macrophage-tropic, subtype B viruses (301660 and JRCSF) detected in a PBMC-based assay. Binding and neutralizing antibodies declined about 10-fold in the 6 months after the last boost. Two vaccinees became infected during the trial, both with subtype E viruses. A phase III efficacy trial, using a bivalent gp120 vaccine containing antigens from a subtype B virus (MN) and a subtype E virus (A244), was initiated in March 1999 in injecting drug users in Bangkok.

Behavioural and serological human immunodeficiency virus risk factors among female commercial sex workers in Cambodia

BACKGROUND

The spread of human immunodeficiency virus (HIV) in Cambodia is mainly caused by sexual transmission and the high-risk group in this country are female commercial sex workers (CSW). There are two types of CSW, direct CSW (DCSW) and indirect CSW (IDCSW), who are different from each other in sexual activities. This study was conducted in order to describe the risk factors on HIV for each type of CSW, and to establish effective preventive strategies against the HIV epidemic among CSW.

METHODS

The participants, 143 DCSW and 94 IDCSW, were interviewed using a questionnaire to determine their demographic characteristics and behaviour. Blood samples were taken for serological tests on HIV, Chlamydia trachomatis and syphilis. The association between their behavioural pattern and their serological results was analysed.

RESULTS

The questionnaire study showed that IDCSW had a riskier behavioural pattern than DCSW. The HIV seroprevalence rates of the DCSW and the IDCSW were 52.4% and 22.3%, respectively. Univariate logistic analyses showed a significant association between HIV antibody (HIV-Ab) and current age, age at commencement of commercial sex work, duration of commercial sex work, and the seropositivity of Chlamydia trachomatis-IgG antibody (CT-IgG-Ab) among the DCSW. The analyses also showed a significant relationship between HIV-Ab and CT-IgG-Ab among the IDCSW.

CONCLUSIONS

Improving condom use rate is very important in order to prevent an HIV epidemic among the two types of CSW. This study also suggests it is important to prevent sexually transmitted disease (STD) such as Chlamydia trachomatis infection. The STD control programme could be efficient for HIV prevention, especially among DCSW.

Highly variable sequences in the env V3 region of HIV type 1 distributing among Thai carriers from 1995 to 1997

The amino acid sequences of the Env V3 region of HIV-1 subtype E in Thailand were highly variable in the samples obtained from 1995 to 1997, compared with the previously reported sequences in samples obtained from 1990 to 1993. The sequences of the V3 region in the samples from five provinces in Thailand revealed that the variability was much higher in the samples from Bangkok and Ubonrachathani than in those from Chiangmai, Prathumthani, and Trang. There was no apparently different level of diversity at the V3 region in the samples from symptomatic and asymptomatic individuals. The V3 loop motif in most (66.7%) of the samples was GPGQ, although this motif was more heterogeneous in the samples from Bangkok and Ubonrachathani than in those from the other three provinces. The N-linked glycosylation sites in the V3 region among these samples were relatively conserved. There was no apparent difference in the presence of positively charged amino acids at positions 306 and 320 between the samples from symptomatic and asymptomatic individuals.

Overland heroin trafficking routes and HIV-1 spread in south and south-east Asia

OBJECTIVES

Burma produces approximately 60% of the world's heroin, Laos is the third leading producer. Recent outbreaks of injecting drug use and HIV-1 in Burma, India, China, and Vietnam have been associated with Burmese and Laotian overland heroin trafficking routes. We analyzed findings from narcotics investigations, molecular epidemiology studies of HIV-1, and epidemiologic and behavioral studies of injecting drug use, to evaluate the roles that the heroin export routes play in the spread of drug use and HIV-1 in south and south-east Asia.

METHODS

We reviewed the medical and narcotics literature, the molecular epidemiology of HIV, and did key informant interviews in India, China, and Burma with injecting drug users, drug traffickers, public health staff, and narcotics control personnel.

RESULTS

Four recent outbreaks of HIV-1 among injecting drug users appear linked to trafficking routes. Route 1: From Burma's eastern border to China's Yunnan Province, with initial spread of HIV-1 subtype B, and later C. Route 2: Eastern Burma to Yunnan, going north and west, to Xinjiang Province, with B, C, and a B/C recombinant subtype. Route 3: Burma and Laos, through northern Vietnam, to China's Guangxi Province, subtype E. Route 4: Western Burma, across the Burma-India border to Manipur, predominant subtype C, and B and E.

CONCLUSIONS

Overland heroin export routes have been associated with dual epidemics of injecting drug use and HIV infection in three Asian countries and along four routes. Molecular epidemiology is useful for mapping heroin routes. Single country narcotics and HIV programs are unlikely to succeed unless the regional narcotic-based economy is addressed.