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Papers by Nancy Young

Research paper thumbnail of These include

The FACSCount flow cytometer absolute CD3 ؉ , CD3 ؉ CD4 ؉ , and CD3 ؉ CD8 ؉ cell counts measured ... more The FACSCount flow cytometer absolute CD3 ؉ , CD3 ؉ CD4 ؉ , and CD3 ؉ CD8 ؉ cell counts measured at a field site hospital laboratory in Thailand were compared to FACScan absolute counts obtained at a nearby research laboratory. Correlation coefficients for 208 samples were >0.95. The FACSCount was accurate, and it was easier and less expensive to operate than the FACScan. Additionally, the FACScan-generated lymphocyte percentage value was accurate for use with the FACScan SimulSET software.

Research paper thumbnail of Evaluation of a Confirmatory HIV Testing Strategy in Thailand not using Western Blot

Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology, 1996

During December 1993-May 1995 in Thailand blood samples were taken from 4818 patients admitted to... more During December 1993-May 1995 in Thailand blood samples were taken from 4818 patients admitted to Bamrasnaradura Infectious Disease Hospital in the Bangkok suburb of Nonthaburi to screen for HIV antibodies using particle agglutination (PA) (SERODIA-HIV Fujirebio Inc. Tokyo Japan). Researchers aimed to evaluate the World Health Organization (WHO) HIV testing strategy II under field conditions by comparing the PA results with those of the enzyme immunoassay (EIA) and the Western blot (WB). The HIV testing strategy II involves a second screening assay instead of the WB to confirm the results of samples reactive on the first screening test to determine HIV seropositivity in asymptomatic persons in areas with HIV prevalence greater than 10% and in persons with suspected HIV infection. PA detected 1173 (24.3%) HIV-positive specimens. All but 3 (99.7%) specimens were reactive by EIA. All but 1 of the 11730 (99.9%) EIA-reactive specimens were also reactive by WB. The 3 EIA-nonreactive specimens and the 1 EIA-reactive specimen were indeterminate by WB. PA alone had a positive predictive value of 99.7%. EIA as the supplemental test had a positive predictive value of 99.9%. These findings support the WHO alternative testing strategy II as a useful strategy for confirming HIV seropositivity among hospital patients with suspected HIV-related disease in Thailand. Studies of the sensitivity and the negative predictive value of the strategy are needed to determine its utility either to screen blood donors or to assess patients with possible HIV infection.

Research paper thumbnail of Early Diagnosis of HIV-1–Infected Infants in Thailand Using RNA and DNA PCR Assays Sensitive to Non-B Subtypes

JAIDS Journal of Acquired Immune Deficiency Syndromes, 2000

To evaluate the sensitivity and specificity of RNA and DNA polymerase chain reaction (PCR) for ea... more To evaluate the sensitivity and specificity of RNA and DNA polymerase chain reaction (PCR) for early diagnosis of perinatal HIV-1 infection and to investigate early viral dynamics in infected infants. A cohort study of 395 non-breastfed infants born to HIV-infected mothers in a randomized clinical trial of short-course antenatal zidovudine. Infant venous blood specimens collected at birth, 2 months, and 6 months of age were tested by qualitative DNA and quantitative RNA PCR (Roche Amplicor). To determine sensitivity and specificity of DNA and RNA PCR, results were compared with later DNA PCR results and to antibody results at 18 months. The HIV-1 subtype of the mother's infection was determined by peptide serotyping. In the study, 92% of mothers were infected with subtype E. DNA PCR sensitivity was 38% (20 of 53) at birth, and 100% at 2 months (53 of 53) and 6 months (47 of 47). RNA PCR sensitivity was 47% (25 of 53) at birth and 100% (53 of 53) at 2 months. All samples that tested DNA-positive tested RNA-positive. Specificity was 100% for both DNA and RNA testing at all timepoints. For infected infants, the median viral load of RNA-positive specimens was 407,000 copies/ml (5.6 log10) at birth, 3, 700,000 copies/ml (6.6 log10) at 2 months, and 1,700,000 copies/ml (6.2 log10) at 6 months. Infant RNA levels at 2 and 6 months did not differ by maternal zidovudine exposure, or RNA level at birth. This RNA PCR assay performed well for diagnosing perinatal HIV subtype E infection, detecting nearly half of infected infants at birth, and 100% at 2 and 6 months, with 100% specificity. Infected infant viral RNA levels were very high at 2 and 6 months, and were unaffected by maternal zidovudine treatment.

Research paper thumbnail of Short-course antenatal zidovudine reduces both cervicovaginal human immunodeficiency virus type 1 RNA levels and risk of perinatal transmission

Journal of Infectious …, 2000

Human immunodeficiency virus (HIV) levels in cervicovaginal lavage (CVL) and plasma samples were ... more Human immunodeficiency virus (HIV) levels in cervicovaginal lavage (CVL) and plasma samples were evaluated in relation to perinatal transmission in a randomized placebo-controlled trial of brief antenatal zidovudine treatment. Samples were collected at 38 weeks' gestation ...

Research paper thumbnail of Prevalence of and risk factors for methamphetamine use in northern Thai youth: results of an audio-computer-assisted self-interviewing survey with urine testing

Addiction, 2002

Data from drug treatment facilities, drug seizures and drug arrests suggest rapidly increasing me... more Data from drug treatment facilities, drug seizures and drug arrests suggest rapidly increasing methamphetamine use by adolescents in Thailand. However, limited quantitative data are available about the prevalence of its use or correlates of use. The purpose of our study was therefore to estimate the prevalence of methamphetamine use and to identify possible risk factors. Cross-sectional survey using anonymous audio-computer-assisted self-interview and urine specimen analysis. Chiang Rai Province, Thailand. 1725 students, 15-21 years of age (893 male and 832 female) attending one of three vocational schools in Chiang Rai Province. Three hundred and fifty male and 150 female students reported a history of having ever used methamphetamine. In addition, 128 male and 49 female students had positive urine test results, indicating recent methamphetamine use; 27 of these students denied having ever used methamphetamine. According to history, urine test, or both, 41.3% of male students and 19.0% of female students used methamphetamine. In multivariate analysis, methamphetamine use was highly correlated with the use of other substances, sexual activity, peer pressure, positive attitudes toward methamphetamine, and absence of a family confidant. Methamphetamine use is common among adolescent students in northern Thailand. Demographic, behavioral and psychosocial correlates of methamphetamine use identified in this study may be helpful for the design and implementation of preventive interventions.

Research paper thumbnail of Mucosal disruption due to use of a widely-distributed commercial vaginal product: potential to facilitate HIV transmission

Aids, 1998

Policresulen vaginal suppositories are a condensation product of metacresolsulfonic acid and form... more Policresulen vaginal suppositories are a condensation product of metacresolsulfonic acid and formaldehyde. We investigated their use by female commercial sex workers (CSW) and whether such use could facilitate HIV transmission. We interviewed female CSW in Thailand about use of the product, and we directly observed the effects of self-administration of a single suppository by each of six women. Of 200 CSW interviewed, 32% had used policresulen vaginal suppositories in the preceding year and 46% had used them at some time. Many used them for reasons not listed on the package insert, such as improving their male partners' sexual pleasure, and most did not abstain from vaginal sex following use. Among 36 brothel-based and 67 non-brothel-based CSW with known HIV infection, the use of the product was not associated with HIV-1 infection (adjusted relative risk 1.0, 95% confidence interval, 0.5-2.0). Exfoliation of the vaginal and cervical mucosa was observed in all six CSW 1 day after product use, and, although it could have been the result of repeated examinations, an increase in genital HIV-1 RNA shedding was also detected in all three HIV-seropositive women. Although there was no epidemiological association with HIV infection, policresulen vaginal suppository use did disrupt the genital mucosa and therefore may have the potential to facilitate HIV transmission. Drug licensing authorities may wish to reassess the safety of this product. If the product continues to be distributed, steps should be taken to limit its use to the specific conditions for which it is indicated and to ensure that women abstain from vaginal sex following its use.

Research paper thumbnail of Infection with HIV-1 subtypes B and E in injecting drug users screened for enrollment into a prospective cohort in Bangkok, Thailand

JAIDS Journal of …, 1998

Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home > ...

Research paper thumbnail of HIV-Specific Cytotoxic T Lymphocytes, HLA-A11, and Chemokine-Related Factors May Act Synergistically to Determine HIV Resistance in CCR5 Δ32-Negative Female Sex Workers in Chiang Rai, Northern Thailand

AIDS Research and Human Retroviruses, 2001

Understanding how highly HIV-exposed individuals remain HIV uninfected may be useful for HIV vacc... more Understanding how highly HIV-exposed individuals remain HIV uninfected may be useful for HIV vaccine design and development of new HIV prevention strategies. To elucidate mechanisms associated with resistance to HIV infection, immunologic and genetic factors were examined in 14 HIV-exposed but persistently seronegative (HEPS) female sex workers from Chiang Rai, northern Thailand and in ethnically matched, HIVpositive (n 5 9) and HIV-negative women (n 5 9). The HEPS women were identified in a study of commercial sex workers who had an HIV-1 incidence of 20.3 per 100 person-years. A high frequency of HLA-A11 was observed in HEPS women (86%) compared with northern Thai controls (56%). HIV-specific cytotoxic T lymphocyte (CTL) lytic responses were detected in cryopreserved peripheral blood mononuclear cells (PBMCs), using HLA-A-matched subtype E HIV-1 peptides in four of seven (57%) HEPS women, eight of eight HIV-positive women, and zero of nine HIV-negative unexposed controls (p 5 0.019 HEPS women vs. HIV-negative controls). CTL lysis levels were low, but responses were detected to peptides from Nef, Pol, Gag, and Env. Nef responses predominated in HEPS women. Compared with controls, HEPS women tended to have higher frequencies of CCR5 promotor 59402GG and SDF-1 39UTR 801A genotypes known to influence HIV transmission or course of disease. HEPS women also had higher levels of spontaneous RANTES production by PBMCs than other groups. Each of these factors could potentially contribute to HIV resistance. As most HEPS women had one or more of these factors, they may prevent HIV infection synergistically by blocking HIV cell entry, delaying its dissemination, or killing HIV-infected cells.

Research paper thumbnail of Viral load differences in early infection with two HIV-1 subtypes

AIDS, 2001

Information on early HIV-1 infection has come primarily from studies of persons infected with sub... more 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. 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. 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. 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.

Research paper thumbnail of Production of a Novel Viral Suppressive Activity Associated with Resistance to Infection among Female Sex Workers Exposed to HIV Type 1

Aids Research and Human Retroviruses, May 20, 2001

To investigate mechanisms of natural resistance to human immunodeficiency virus type 1 (HIV-1), w... more To investigate mechanisms of natural resistance to human immunodeficiency virus type 1 (HIV-1), we obtained blood samples from eight women who remained HIV-1 negative after > 3 years of high-risk sex work in Chiang Rai, Thailand. CD4+ T lymphocytes from these highly exposed, persistently seronegative (HEPS) women were readily infectable in vitro with HIV-1 subtypes B and E. Autologous CD8+ cell suppression of both HIV-1 subtypes was evident in HEPS infection cultures, but to an extent also observed in cultures from non-HIV-exposed individuals. Furthermore, production of beta-chemokines was not enhanced in HEPS cultures. However, HEPS cultures displayed significantly enhanced production of a soluble activity that suppressed postintegrated HIV-1 replication. This activity was the unique product of CD4+ T cell and monocyte cocultures. Therefore, although HEPS individuals are apparently susceptible to infection, the production of a postintegrated HIV-1 suppressive activity during monocyte-T cell interactions might protect against the establishment of infection by limiting viral dissemination.

Research paper thumbnail of The evolving molecular epidemiology of HIV-1 envelope subtypes in injecting drug users in Bangkok, Thailand: implications for HIV vaccine trials

Aids, 1995

To genetically characterize HIV-1 strains in injecting drug users (IDU) in Bangkok, Thailand in 1... more To genetically characterize HIV-1 strains in injecting drug users (IDU) in Bangkok, Thailand in 1994, and compare these with strains found earlier in Thai IDU; such information is essential for HIV-1 vaccine development and evaluation. Peripheral blood mononuclear cells were collected from 84 IDU attending 14 drug treatment clinics in Bangkok in 1994. DNA was amplified using a nested polymerase chain reaction (PCR) procedure and sequenced directly (without cloning) from the PCR products. The V3 and flanking regions (345 nucleotides) of the env gene were analyzed using a neighbor-joining tree. Only one (1%) strain was a typical subtype B virus, 69 (82%) were genetically distinct subtype B' viruses (Thai B), and 14 (17%) were subtype E strains (Thai A). Persons with recently acquired infection were more likely to have subtype E viruses (P < 0.001) than those in our 1991 survey, who were more likely to have subtype B' viruses. Pairwise intra-subtype differences within subtypes E and B' were 5.3 and 4.3%, respectively, compared with 3.4 and 3.5% among strains collected in 1991 in Thailand. The genetic diversity within subtypes B' and E in Thailand and the proportion of new infections due to subtype E viruses among Bangkok IDU are increasing significantly. These data highlight the importance of monitoring the molecular epidemiology of HIV-1 in populations being considered for HIV-1 vaccine trials.

Research paper thumbnail of Highly specific V3 peptide enzyme immunoassay for seretyping HIV-1 specimens from Thailand

Aids, 1993

To develop and evaluate a simple V3 peptide-based enzyme immunoassay (EIA) for large-scale seroty... more To develop and evaluate a simple V3 peptide-based enzyme immunoassay (EIA) for large-scale serotyping of HIV-1 specimens from Thailand. Serologic reactivities with synthetic peptides derived from the V3 loop of gp120 were used for typing HIV-1 specimens. Synthetic peptides PND-A and PND-B, derived from the consensus amino-acid sequences of the V3 loop of gp120 from two major genomic variants of HIV-1 in Thailand (A and B), were evaluated in an EIA on 61 Thai HIV-1 sera for which genotypes had been determined by polymerase chain reaction. The peptide EIA was then applied to sera from 188 HIV-1-infected patients, selected in non-random, convenience samples of known risk groups from four geographic regions of Thailand. The sensitivities and specificities of PND-A and PND-B were 86% (30 out of 35) and 96% (25 out of 26) and 92% (24 out of 26) and 94% (33 out of 35), respectively, with 100% predictive values of a monoreactive positive test for both peptides. The assay classified 101 specimens as serotype A, 39 as serotype B, eight as serotype AB (dually reactive), and 40 as untypable (non-reactive). Excluding dual reactors and non-reactors, 92% (77 out of 84) of specimens from patients probably infected by sexual contact were serotype A; conversely, 76% (28 out of 37) of injecting drug users were serotype B. The serologic results corroborated previous findings, in a smaller subset of samples, of an apparent segregation of viral subtypes by mode of transmission, suggesting two separate HIV-1 epidemics in Thailand. This peptide EIA could be a valuable epidemiologic tool in determining the dynamics of the rapid spread of HIV-1 in Thailand.

Research paper thumbnail of Clinical field site evaluation of the FACSCount for absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell count determinations in Thailand

Clinical and diagnostic laboratory immunology, 1997

The FACSCount flow cytometer absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell counts measured at a fi... more The FACSCount flow cytometer absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell counts measured at a field site hospital laboratory in Thailand were compared to FACScan absolute counts obtained at a nearby research laboratory. Correlation coefficients for 208 samples were > or = 0.95. The FACSCount was accurate, and it was easier and less expensive to operate than the FACScan. Additionally, the FACScan-generated lymphocyte percentage value was accurate for use with the FACScan SimulSET software.

Research paper thumbnail of Detection of genetically diverse human immunodeficiency virus type 1 group M and O isolates by PCR

Journal of clinical microbiology, 1997

A panel of 136 genetically diverse group M and 5 group O adult isolates from outside the United S... more A panel of 136 genetically diverse group M and 5 group O adult isolates from outside the United States and Europe were evaluated by PCR with the Roche AMPLICOR HIV-1 test, a modified version of the AMPLICOR HIV-1 test, and a new primer pair/probe system. Detection of some of these isolates was less efficient with the AMPLICOR HIV-1 test; however, the assay was significantly improved by reducing the sample input and lowering the annealing temperature. The new primer pair/probe set detected 140 of 141 isolates, including the 5 group O isolates that were not detected with either of the AMPLICOR HIV-1 test formats.

Research paper thumbnail of Modified Amplicor HIV-1 Polymerase Chain Reaction Assay in Thailand

Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology, 1997

Research paper thumbnail of HIV-1 Subtype E Incidence and Sexually Transmitted Diseases in a Cohort of Military Conscripts in Northern Thailand

Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology, 1998

To determine the rate of and risk factors for HIV-1 seroconversion and describe sexually transmit... more To determine the rate of and risk factors for HIV-1 seroconversion and describe sexually transmitted disease (STD) prevalence rates for young men in northern Thailand. Data were collected from self-administered questionnaires and serologic testing at enrollment in a prospective study in 1991 and at follow-up after 6, 17, and 23 months on a cohort of 1115 men selected by lottery for military conscription. A total of 14 men seroconverted to HIV-1 envelope subtype E. The overall HIV-1 incidence rate was 1.1 (95% confidence interval [CI], 0.6-1.8) per 100 person-years (PY) of follow-up. However, the rate was 2.0/100 PY for conscripts from the upper northern subregion of Thailand compared with 0.5/100 PY from other regions (adjusted rate ratio [RR] = 2.69; 95% CI, 0.8-12.2). On multivariate analyses, the behavioral factors associated with HIV-1 seroconversion were frequency of sex with female sex workers (FSWs; p = .04), receptive anal sex (adjusted RR = 6.73; 95% CI, 1.8-21.7), and large amount of alcohol consumption (adjusted RR = 3.12; 95% CI, 1.0-10.9). Genital ulceration was the STD most strongly associated with seroconversion. The prevalence of serologic reactivity to syphilis, Haemophilus ducreyi, and herpes simplex virus type 2 increased with greater frequency of sex with FSWs and was generally higher for men from the upper north. Young men in northern Thailand are at high risk for HIV-1, primarily through sex with FSWs; and other STDs are highly associated with HIV-1 incidence. As HIV-1 infection extends into the general population, intervention programs are needed to address the problem of sexual transmission apart from commercial sex venues.

Research paper thumbnail of Rapid assessment of sexually transmitted diseases in a sentinel population in Thailand: prevalence of chlamydial infection, gonorrhoea, and syphilis among pregnant women--1996

Sexually Transmitted Infections, 1998

To determine the prevalence of sexually transmitted diseases (STDs) among pregnant women in Thail... more To determine the prevalence of sexually transmitted diseases (STDs) among pregnant women in Thailand, where case reporting suggests a marked decrease in STDs following a campaign promoting condom use during commercial sex. Design: Cross sectional study of women at their first visit to the study hospitals' antenatal clinics in Chiang Rai (n=500) and Bangkok (n=521). Methods: First catch urine specimens were tested for Chlamydia trachomatis and Neisseria gonorrhoeae using the Amplicor CT/NG polymerase chain reaction assay. Syphilis and HIV serological testing were performed in the study hospitals' laboratories. Results: The prevalence of chlamydial infection was 5.7%, gonorrhoea 0.2%, and syphilis 0.5% (all VDRL or RPR titres were <1:4). The prevalence of HIV infection was 7.1% in Chiang Rai and 2.9% in Bangkok. In a multivariate logistic regression analysis, chlamydial infection was associated with younger age and with higher gestational age at first antenatal clinic visit, but was not associated with marital status, gravidity, city of enrolment, or HIV infection status. Conclusions: There was a low prevalence of gonorrhoea and syphilis among these pregnant women in Thailand. Chlamydial infection was detected at a higher prevalence, especially among younger women and women registering later for antenatal care. Testing of pregnant women using easily collected urine specimens and a sensitive nucleic acid amplification assay is a feasible method of rapidly assessing chlamydial and gonococcal prevalence.

Research paper thumbnail of HIV-1 and other sexually transmitted infections in a cohort of female sex workers in Chiang Rai, Thailand

Sexually Transmitted Infections, 1999

Objectives: To determine demographic and behavioural factors and sexually transmitted infections ... more Objectives: To determine demographic and behavioural factors and sexually transmitted infections (STIs) associated with prevalent HIV-1 infection among brothel based and other female sex workers (FSWs) in Chiang Rai, northern Thailand. Methods: Data were collected from questionnaires, physical examinations, and laboratory evaluations on Thai FSWs enrolled in a prospective cohort study in Chiang Rai, Thailand, from 1991 to the end of 1994. Results: HIV-1 seroprevalence was 32% among 500 women: 47% for 280 brothel workers and 13% for 220 other FSWs (p<0.001); 96% of infections were due to HIV-1 subtype E. At enrolment, other STIs were common: chlamydia, 20%; gonorrhoea, 15%; active syphilis (serological diagnosis), 9%; genital ulcer, 12%; seroreactivity to Haemophilus ducreyi, 21%, and herpes simplex virus type 2 (HSV-2), 76%. On multiple logistic regression analysis, HIV-1 was associated with brothel work, birth in upper northern Thailand, initiation of commercial sex at <15 years of age, syphilis, HSV-2 seropositivity, and genital ulcer. Conclusions: Young Thai FSWs working in brothels in northern Thailand in the early phase of the HIV epidemic have been at very high risk for HIV-1 infection and several other STIs. Programmes are needed to prevent girls and young women from entering the sex industry and to reduce the risk of infection with HIV-1 and other STIs.

Research paper thumbnail of Chlamydial and Gonococcal Cervicitis in HIV-Seropositive and HIV-Seronegative Pregnant Women in Bangkok

Sexually Transmitted Diseases, 1997

To determine the prevalence and risk factors associated with cervicitis caused by Chlamydia trach... more To determine the prevalence and risk factors associated with cervicitis caused by Chlamydia trachomatis and Neisseria gonorrhoeae in human immunodeficiency virus (HIV) type 1-seropositive and HIV-seronegative pregnant women in Bangkok, and the relation to perinatal HIV transmission. As part of a multicenter perinatal HIV transmission study in an antenatal population with 2% HIV seroprevalence, endocervical swabs obtained at mid-pregnancy from a consecutive sample of 222 HIV-seropositive and 219 HIV-seronegative pregnant women at two large hospitals in Bangkok were tested for the presence of C. trachomatis and N. gonorrhoeae by DNA hybridization probe (Gen-Probe). Clinical risk factors and DNA probe results were analyzed in relation to the women&#39;s and newborns&#39; HIV infection status. The prevalence of C. trachomatis was 16.2% in HIV-seropositive pregnant women and 9.1% in HIV-seronegative pregnant women (P = 0.03). The prevalence of N. gonorrhoeae was 2.7% in HIV-seropositive pregnant women and 1.4% in HIV-seronegative pregnant women (P = 0.5). The overall population prevalence estimate was 9.2% for C. trachomatis and 1.4% for N. gonorrhoeae. Women with gonococcal infection were more likely to be positive for C. trachomatis (RR(MH) = 5.2, P &lt; 0.01). Young age (&lt;21 years) and primigravid status were associated with C. trachomatis infection among HIV-seropositive women; history of multiple sex partners (&gt;1) were associated with C. trachomatis infection among HIV-seronegative women. For HIV-seropositive women, primigravida status also was associated with C. trachomatis infection. The perinatal HIV transmission rates were similar for those with and without C. trachomatis (24.1% and 23.2%, P = 0.9) and among those with and without N. gonorrhoeae (20% and 23.5%, P = 1.0). Among pregnant women in Bangkok, C. trachomatis infection was considerably more common than N. gonorrhoeae infection and was associated with HIV infection, young age and first pregnancy (HIV-seropositive women), and multiple partners (HIV-seronegative women). Our data do not suggest an association between perinatal HIV transmission and maternal C. trachomatis or N. gonorrhoeae infection identified and treated during pregnancy. The high prevalence of C. trachomatis found using a test not readily available in Thailand emphasizes the need for improved, inexpensive ways to screen for and diagnose these sexually transmitted infections in developing countries.

Research paper thumbnail of Safety of Late In Utero Exposure to Zidovudine in Infants Born to Human Immunodeficiency Virus-Infected Mothers: Bangkok

PEDIATRICS, 2001

, for the Bangkok Collaborative Perinatal HIV Transmission Study Group ABSTRACT. Background. Shor... more , for the Bangkok Collaborative Perinatal HIV Transmission Study Group ABSTRACT. Background. Short-course zidovudine (ZDV) given in the late antenatal period can reduce mother-infant human immunodeficiency virus (HIV) transmission by one half. Because this intervention is being implemented in developing countries, evidence of its safety is needed. Methods. In a randomized, double-blinded, placebocontrolled trial in Bangkok, HIV-infected pregnant women received either ZDV (300 mg twice daily from 36 weeks' gestation until labor, then every 3 hours until delivery) or an identical placebo regimen. Infants were evaluated at birth and at 1, 2, 4, 6, 9, 12, 15, and 18 months of age. Growth, clinical events, and hematologic and immunologic measurements were compared between treatment groups. Results. Of the 395 children born (196 in ZDV group and 199 in placebo group), 330 were uninfected, 55 were infected, and 10 had indeterminate infection status. Overall, 319 children (81%) completed 18 months of follow-up, and 14 (4%) died before 18 months of age. Among uninfected children, the mean hematocrit was lower in the ZDV group at birth (49.1% vs 51.5%) but not at later ages; mean weight, height, head circumference, and CD4 ؉ and CD8 ؉ T lymphocyte counts were similar in both groups at all ages. Five uninfected children in the ZDV group but only one in the placebo group had a febrile convulsion. No other signs suggestive of mitochondrial dysfunction and no tumors were observed. Among infected children, an estimated 62% in the ZDV group and 77% in the placebo group survived free of Centers for Disease Control and Prevention class C disease during the 18-month follow-up. Conclusions. No significant adverse events were associated with short-course ZDV during 18 months of follow-up in this population.

Research paper thumbnail of These include

The FACSCount flow cytometer absolute CD3 ؉ , CD3 ؉ CD4 ؉ , and CD3 ؉ CD8 ؉ cell counts measured ... more The FACSCount flow cytometer absolute CD3 ؉ , CD3 ؉ CD4 ؉ , and CD3 ؉ CD8 ؉ cell counts measured at a field site hospital laboratory in Thailand were compared to FACScan absolute counts obtained at a nearby research laboratory. Correlation coefficients for 208 samples were >0.95. The FACSCount was accurate, and it was easier and less expensive to operate than the FACScan. Additionally, the FACScan-generated lymphocyte percentage value was accurate for use with the FACScan SimulSET software.

Research paper thumbnail of Evaluation of a Confirmatory HIV Testing Strategy in Thailand not using Western Blot

Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology, 1996

During December 1993-May 1995 in Thailand blood samples were taken from 4818 patients admitted to... more During December 1993-May 1995 in Thailand blood samples were taken from 4818 patients admitted to Bamrasnaradura Infectious Disease Hospital in the Bangkok suburb of Nonthaburi to screen for HIV antibodies using particle agglutination (PA) (SERODIA-HIV Fujirebio Inc. Tokyo Japan). Researchers aimed to evaluate the World Health Organization (WHO) HIV testing strategy II under field conditions by comparing the PA results with those of the enzyme immunoassay (EIA) and the Western blot (WB). The HIV testing strategy II involves a second screening assay instead of the WB to confirm the results of samples reactive on the first screening test to determine HIV seropositivity in asymptomatic persons in areas with HIV prevalence greater than 10% and in persons with suspected HIV infection. PA detected 1173 (24.3%) HIV-positive specimens. All but 3 (99.7%) specimens were reactive by EIA. All but 1 of the 11730 (99.9%) EIA-reactive specimens were also reactive by WB. The 3 EIA-nonreactive specimens and the 1 EIA-reactive specimen were indeterminate by WB. PA alone had a positive predictive value of 99.7%. EIA as the supplemental test had a positive predictive value of 99.9%. These findings support the WHO alternative testing strategy II as a useful strategy for confirming HIV seropositivity among hospital patients with suspected HIV-related disease in Thailand. Studies of the sensitivity and the negative predictive value of the strategy are needed to determine its utility either to screen blood donors or to assess patients with possible HIV infection.

Research paper thumbnail of Early Diagnosis of HIV-1–Infected Infants in Thailand Using RNA and DNA PCR Assays Sensitive to Non-B Subtypes

JAIDS Journal of Acquired Immune Deficiency Syndromes, 2000

To evaluate the sensitivity and specificity of RNA and DNA polymerase chain reaction (PCR) for ea... more To evaluate the sensitivity and specificity of RNA and DNA polymerase chain reaction (PCR) for early diagnosis of perinatal HIV-1 infection and to investigate early viral dynamics in infected infants. A cohort study of 395 non-breastfed infants born to HIV-infected mothers in a randomized clinical trial of short-course antenatal zidovudine. Infant venous blood specimens collected at birth, 2 months, and 6 months of age were tested by qualitative DNA and quantitative RNA PCR (Roche Amplicor). To determine sensitivity and specificity of DNA and RNA PCR, results were compared with later DNA PCR results and to antibody results at 18 months. The HIV-1 subtype of the mother&#39;s infection was determined by peptide serotyping. In the study, 92% of mothers were infected with subtype E. DNA PCR sensitivity was 38% (20 of 53) at birth, and 100% at 2 months (53 of 53) and 6 months (47 of 47). RNA PCR sensitivity was 47% (25 of 53) at birth and 100% (53 of 53) at 2 months. All samples that tested DNA-positive tested RNA-positive. Specificity was 100% for both DNA and RNA testing at all timepoints. For infected infants, the median viral load of RNA-positive specimens was 407,000 copies/ml (5.6 log10) at birth, 3, 700,000 copies/ml (6.6 log10) at 2 months, and 1,700,000 copies/ml (6.2 log10) at 6 months. Infant RNA levels at 2 and 6 months did not differ by maternal zidovudine exposure, or RNA level at birth. This RNA PCR assay performed well for diagnosing perinatal HIV subtype E infection, detecting nearly half of infected infants at birth, and 100% at 2 and 6 months, with 100% specificity. Infected infant viral RNA levels were very high at 2 and 6 months, and were unaffected by maternal zidovudine treatment.

Research paper thumbnail of Short-course antenatal zidovudine reduces both cervicovaginal human immunodeficiency virus type 1 RNA levels and risk of perinatal transmission

Journal of Infectious …, 2000

Human immunodeficiency virus (HIV) levels in cervicovaginal lavage (CVL) and plasma samples were ... more Human immunodeficiency virus (HIV) levels in cervicovaginal lavage (CVL) and plasma samples were evaluated in relation to perinatal transmission in a randomized placebo-controlled trial of brief antenatal zidovudine treatment. Samples were collected at 38 weeks' gestation ...

Research paper thumbnail of Prevalence of and risk factors for methamphetamine use in northern Thai youth: results of an audio-computer-assisted self-interviewing survey with urine testing

Addiction, 2002

Data from drug treatment facilities, drug seizures and drug arrests suggest rapidly increasing me... more Data from drug treatment facilities, drug seizures and drug arrests suggest rapidly increasing methamphetamine use by adolescents in Thailand. However, limited quantitative data are available about the prevalence of its use or correlates of use. The purpose of our study was therefore to estimate the prevalence of methamphetamine use and to identify possible risk factors. Cross-sectional survey using anonymous audio-computer-assisted self-interview and urine specimen analysis. Chiang Rai Province, Thailand. 1725 students, 15-21 years of age (893 male and 832 female) attending one of three vocational schools in Chiang Rai Province. Three hundred and fifty male and 150 female students reported a history of having ever used methamphetamine. In addition, 128 male and 49 female students had positive urine test results, indicating recent methamphetamine use; 27 of these students denied having ever used methamphetamine. According to history, urine test, or both, 41.3% of male students and 19.0% of female students used methamphetamine. In multivariate analysis, methamphetamine use was highly correlated with the use of other substances, sexual activity, peer pressure, positive attitudes toward methamphetamine, and absence of a family confidant. Methamphetamine use is common among adolescent students in northern Thailand. Demographic, behavioral and psychosocial correlates of methamphetamine use identified in this study may be helpful for the design and implementation of preventive interventions.

Research paper thumbnail of Mucosal disruption due to use of a widely-distributed commercial vaginal product: potential to facilitate HIV transmission

Aids, 1998

Policresulen vaginal suppositories are a condensation product of metacresolsulfonic acid and form... more Policresulen vaginal suppositories are a condensation product of metacresolsulfonic acid and formaldehyde. We investigated their use by female commercial sex workers (CSW) and whether such use could facilitate HIV transmission. We interviewed female CSW in Thailand about use of the product, and we directly observed the effects of self-administration of a single suppository by each of six women. Of 200 CSW interviewed, 32% had used policresulen vaginal suppositories in the preceding year and 46% had used them at some time. Many used them for reasons not listed on the package insert, such as improving their male partners&amp;amp;#39; sexual pleasure, and most did not abstain from vaginal sex following use. Among 36 brothel-based and 67 non-brothel-based CSW with known HIV infection, the use of the product was not associated with HIV-1 infection (adjusted relative risk 1.0, 95% confidence interval, 0.5-2.0). Exfoliation of the vaginal and cervical mucosa was observed in all six CSW 1 day after product use, and, although it could have been the result of repeated examinations, an increase in genital HIV-1 RNA shedding was also detected in all three HIV-seropositive women. Although there was no epidemiological association with HIV infection, policresulen vaginal suppository use did disrupt the genital mucosa and therefore may have the potential to facilitate HIV transmission. Drug licensing authorities may wish to reassess the safety of this product. If the product continues to be distributed, steps should be taken to limit its use to the specific conditions for which it is indicated and to ensure that women abstain from vaginal sex following its use.

Research paper thumbnail of Infection with HIV-1 subtypes B and E in injecting drug users screened for enrollment into a prospective cohort in Bangkok, Thailand

JAIDS Journal of …, 1998

Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home > ...

Research paper thumbnail of HIV-Specific Cytotoxic T Lymphocytes, HLA-A11, and Chemokine-Related Factors May Act Synergistically to Determine HIV Resistance in CCR5 Δ32-Negative Female Sex Workers in Chiang Rai, Northern Thailand

AIDS Research and Human Retroviruses, 2001

Understanding how highly HIV-exposed individuals remain HIV uninfected may be useful for HIV vacc... more Understanding how highly HIV-exposed individuals remain HIV uninfected may be useful for HIV vaccine design and development of new HIV prevention strategies. To elucidate mechanisms associated with resistance to HIV infection, immunologic and genetic factors were examined in 14 HIV-exposed but persistently seronegative (HEPS) female sex workers from Chiang Rai, northern Thailand and in ethnically matched, HIVpositive (n 5 9) and HIV-negative women (n 5 9). The HEPS women were identified in a study of commercial sex workers who had an HIV-1 incidence of 20.3 per 100 person-years. A high frequency of HLA-A11 was observed in HEPS women (86%) compared with northern Thai controls (56%). HIV-specific cytotoxic T lymphocyte (CTL) lytic responses were detected in cryopreserved peripheral blood mononuclear cells (PBMCs), using HLA-A-matched subtype E HIV-1 peptides in four of seven (57%) HEPS women, eight of eight HIV-positive women, and zero of nine HIV-negative unexposed controls (p 5 0.019 HEPS women vs. HIV-negative controls). CTL lysis levels were low, but responses were detected to peptides from Nef, Pol, Gag, and Env. Nef responses predominated in HEPS women. Compared with controls, HEPS women tended to have higher frequencies of CCR5 promotor 59402GG and SDF-1 39UTR 801A genotypes known to influence HIV transmission or course of disease. HEPS women also had higher levels of spontaneous RANTES production by PBMCs than other groups. Each of these factors could potentially contribute to HIV resistance. As most HEPS women had one or more of these factors, they may prevent HIV infection synergistically by blocking HIV cell entry, delaying its dissemination, or killing HIV-infected cells.

Research paper thumbnail of Viral load differences in early infection with two HIV-1 subtypes

AIDS, 2001

Information on early HIV-1 infection has come primarily from studies of persons infected with sub... more 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. 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. 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. 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.

Research paper thumbnail of Production of a Novel Viral Suppressive Activity Associated with Resistance to Infection among Female Sex Workers Exposed to HIV Type 1

Aids Research and Human Retroviruses, May 20, 2001

To investigate mechanisms of natural resistance to human immunodeficiency virus type 1 (HIV-1), w... more To investigate mechanisms of natural resistance to human immunodeficiency virus type 1 (HIV-1), we obtained blood samples from eight women who remained HIV-1 negative after &gt; 3 years of high-risk sex work in Chiang Rai, Thailand. CD4+ T lymphocytes from these highly exposed, persistently seronegative (HEPS) women were readily infectable in vitro with HIV-1 subtypes B and E. Autologous CD8+ cell suppression of both HIV-1 subtypes was evident in HEPS infection cultures, but to an extent also observed in cultures from non-HIV-exposed individuals. Furthermore, production of beta-chemokines was not enhanced in HEPS cultures. However, HEPS cultures displayed significantly enhanced production of a soluble activity that suppressed postintegrated HIV-1 replication. This activity was the unique product of CD4+ T cell and monocyte cocultures. Therefore, although HEPS individuals are apparently susceptible to infection, the production of a postintegrated HIV-1 suppressive activity during monocyte-T cell interactions might protect against the establishment of infection by limiting viral dissemination.

Research paper thumbnail of The evolving molecular epidemiology of HIV-1 envelope subtypes in injecting drug users in Bangkok, Thailand: implications for HIV vaccine trials

Aids, 1995

To genetically characterize HIV-1 strains in injecting drug users (IDU) in Bangkok, Thailand in 1... more To genetically characterize HIV-1 strains in injecting drug users (IDU) in Bangkok, Thailand in 1994, and compare these with strains found earlier in Thai IDU; such information is essential for HIV-1 vaccine development and evaluation. Peripheral blood mononuclear cells were collected from 84 IDU attending 14 drug treatment clinics in Bangkok in 1994. DNA was amplified using a nested polymerase chain reaction (PCR) procedure and sequenced directly (without cloning) from the PCR products. The V3 and flanking regions (345 nucleotides) of the env gene were analyzed using a neighbor-joining tree. Only one (1%) strain was a typical subtype B virus, 69 (82%) were genetically distinct subtype B&#39; viruses (Thai B), and 14 (17%) were subtype E strains (Thai A). Persons with recently acquired infection were more likely to have subtype E viruses (P &lt; 0.001) than those in our 1991 survey, who were more likely to have subtype B&#39; viruses. Pairwise intra-subtype differences within subtypes E and B&#39; were 5.3 and 4.3%, respectively, compared with 3.4 and 3.5% among strains collected in 1991 in Thailand. The genetic diversity within subtypes B&#39; and E in Thailand and the proportion of new infections due to subtype E viruses among Bangkok IDU are increasing significantly. These data highlight the importance of monitoring the molecular epidemiology of HIV-1 in populations being considered for HIV-1 vaccine trials.

Research paper thumbnail of Highly specific V3 peptide enzyme immunoassay for seretyping HIV-1 specimens from Thailand

Aids, 1993

To develop and evaluate a simple V3 peptide-based enzyme immunoassay (EIA) for large-scale seroty... more To develop and evaluate a simple V3 peptide-based enzyme immunoassay (EIA) for large-scale serotyping of HIV-1 specimens from Thailand. Serologic reactivities with synthetic peptides derived from the V3 loop of gp120 were used for typing HIV-1 specimens. Synthetic peptides PND-A and PND-B, derived from the consensus amino-acid sequences of the V3 loop of gp120 from two major genomic variants of HIV-1 in Thailand (A and B), were evaluated in an EIA on 61 Thai HIV-1 sera for which genotypes had been determined by polymerase chain reaction. The peptide EIA was then applied to sera from 188 HIV-1-infected patients, selected in non-random, convenience samples of known risk groups from four geographic regions of Thailand. The sensitivities and specificities of PND-A and PND-B were 86% (30 out of 35) and 96% (25 out of 26) and 92% (24 out of 26) and 94% (33 out of 35), respectively, with 100% predictive values of a monoreactive positive test for both peptides. The assay classified 101 specimens as serotype A, 39 as serotype B, eight as serotype AB (dually reactive), and 40 as untypable (non-reactive). Excluding dual reactors and non-reactors, 92% (77 out of 84) of specimens from patients probably infected by sexual contact were serotype A; conversely, 76% (28 out of 37) of injecting drug users were serotype B. The serologic results corroborated previous findings, in a smaller subset of samples, of an apparent segregation of viral subtypes by mode of transmission, suggesting two separate HIV-1 epidemics in Thailand. This peptide EIA could be a valuable epidemiologic tool in determining the dynamics of the rapid spread of HIV-1 in Thailand.

Research paper thumbnail of Clinical field site evaluation of the FACSCount for absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell count determinations in Thailand

Clinical and diagnostic laboratory immunology, 1997

The FACSCount flow cytometer absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell counts measured at a fi... more The FACSCount flow cytometer absolute CD3+, CD3+ CD4+, and CD3+ CD8+ cell counts measured at a field site hospital laboratory in Thailand were compared to FACScan absolute counts obtained at a nearby research laboratory. Correlation coefficients for 208 samples were > or = 0.95. The FACSCount was accurate, and it was easier and less expensive to operate than the FACScan. Additionally, the FACScan-generated lymphocyte percentage value was accurate for use with the FACScan SimulSET software.

Research paper thumbnail of Detection of genetically diverse human immunodeficiency virus type 1 group M and O isolates by PCR

Journal of clinical microbiology, 1997

A panel of 136 genetically diverse group M and 5 group O adult isolates from outside the United S... more A panel of 136 genetically diverse group M and 5 group O adult isolates from outside the United States and Europe were evaluated by PCR with the Roche AMPLICOR HIV-1 test, a modified version of the AMPLICOR HIV-1 test, and a new primer pair/probe system. Detection of some of these isolates was less efficient with the AMPLICOR HIV-1 test; however, the assay was significantly improved by reducing the sample input and lowering the annealing temperature. The new primer pair/probe set detected 140 of 141 isolates, including the 5 group O isolates that were not detected with either of the AMPLICOR HIV-1 test formats.

Research paper thumbnail of Modified Amplicor HIV-1 Polymerase Chain Reaction Assay in Thailand

Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology, 1997

Research paper thumbnail of HIV-1 Subtype E Incidence and Sexually Transmitted Diseases in a Cohort of Military Conscripts in Northern Thailand

Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology, 1998

To determine the rate of and risk factors for HIV-1 seroconversion and describe sexually transmit... more To determine the rate of and risk factors for HIV-1 seroconversion and describe sexually transmitted disease (STD) prevalence rates for young men in northern Thailand. Data were collected from self-administered questionnaires and serologic testing at enrollment in a prospective study in 1991 and at follow-up after 6, 17, and 23 months on a cohort of 1115 men selected by lottery for military conscription. A total of 14 men seroconverted to HIV-1 envelope subtype E. The overall HIV-1 incidence rate was 1.1 (95% confidence interval [CI], 0.6-1.8) per 100 person-years (PY) of follow-up. However, the rate was 2.0/100 PY for conscripts from the upper northern subregion of Thailand compared with 0.5/100 PY from other regions (adjusted rate ratio [RR] = 2.69; 95% CI, 0.8-12.2). On multivariate analyses, the behavioral factors associated with HIV-1 seroconversion were frequency of sex with female sex workers (FSWs; p = .04), receptive anal sex (adjusted RR = 6.73; 95% CI, 1.8-21.7), and large amount of alcohol consumption (adjusted RR = 3.12; 95% CI, 1.0-10.9). Genital ulceration was the STD most strongly associated with seroconversion. The prevalence of serologic reactivity to syphilis, Haemophilus ducreyi, and herpes simplex virus type 2 increased with greater frequency of sex with FSWs and was generally higher for men from the upper north. Young men in northern Thailand are at high risk for HIV-1, primarily through sex with FSWs; and other STDs are highly associated with HIV-1 incidence. As HIV-1 infection extends into the general population, intervention programs are needed to address the problem of sexual transmission apart from commercial sex venues.

Research paper thumbnail of Rapid assessment of sexually transmitted diseases in a sentinel population in Thailand: prevalence of chlamydial infection, gonorrhoea, and syphilis among pregnant women--1996

Sexually Transmitted Infections, 1998

To determine the prevalence of sexually transmitted diseases (STDs) among pregnant women in Thail... more To determine the prevalence of sexually transmitted diseases (STDs) among pregnant women in Thailand, where case reporting suggests a marked decrease in STDs following a campaign promoting condom use during commercial sex. Design: Cross sectional study of women at their first visit to the study hospitals' antenatal clinics in Chiang Rai (n=500) and Bangkok (n=521). Methods: First catch urine specimens were tested for Chlamydia trachomatis and Neisseria gonorrhoeae using the Amplicor CT/NG polymerase chain reaction assay. Syphilis and HIV serological testing were performed in the study hospitals' laboratories. Results: The prevalence of chlamydial infection was 5.7%, gonorrhoea 0.2%, and syphilis 0.5% (all VDRL or RPR titres were <1:4). The prevalence of HIV infection was 7.1% in Chiang Rai and 2.9% in Bangkok. In a multivariate logistic regression analysis, chlamydial infection was associated with younger age and with higher gestational age at first antenatal clinic visit, but was not associated with marital status, gravidity, city of enrolment, or HIV infection status. Conclusions: There was a low prevalence of gonorrhoea and syphilis among these pregnant women in Thailand. Chlamydial infection was detected at a higher prevalence, especially among younger women and women registering later for antenatal care. Testing of pregnant women using easily collected urine specimens and a sensitive nucleic acid amplification assay is a feasible method of rapidly assessing chlamydial and gonococcal prevalence.

Research paper thumbnail of HIV-1 and other sexually transmitted infections in a cohort of female sex workers in Chiang Rai, Thailand

Sexually Transmitted Infections, 1999

Objectives: To determine demographic and behavioural factors and sexually transmitted infections ... more Objectives: To determine demographic and behavioural factors and sexually transmitted infections (STIs) associated with prevalent HIV-1 infection among brothel based and other female sex workers (FSWs) in Chiang Rai, northern Thailand. Methods: Data were collected from questionnaires, physical examinations, and laboratory evaluations on Thai FSWs enrolled in a prospective cohort study in Chiang Rai, Thailand, from 1991 to the end of 1994. Results: HIV-1 seroprevalence was 32% among 500 women: 47% for 280 brothel workers and 13% for 220 other FSWs (p<0.001); 96% of infections were due to HIV-1 subtype E. At enrolment, other STIs were common: chlamydia, 20%; gonorrhoea, 15%; active syphilis (serological diagnosis), 9%; genital ulcer, 12%; seroreactivity to Haemophilus ducreyi, 21%, and herpes simplex virus type 2 (HSV-2), 76%. On multiple logistic regression analysis, HIV-1 was associated with brothel work, birth in upper northern Thailand, initiation of commercial sex at <15 years of age, syphilis, HSV-2 seropositivity, and genital ulcer. Conclusions: Young Thai FSWs working in brothels in northern Thailand in the early phase of the HIV epidemic have been at very high risk for HIV-1 infection and several other STIs. Programmes are needed to prevent girls and young women from entering the sex industry and to reduce the risk of infection with HIV-1 and other STIs.

Research paper thumbnail of Chlamydial and Gonococcal Cervicitis in HIV-Seropositive and HIV-Seronegative Pregnant Women in Bangkok

Sexually Transmitted Diseases, 1997

To determine the prevalence and risk factors associated with cervicitis caused by Chlamydia trach... more To determine the prevalence and risk factors associated with cervicitis caused by Chlamydia trachomatis and Neisseria gonorrhoeae in human immunodeficiency virus (HIV) type 1-seropositive and HIV-seronegative pregnant women in Bangkok, and the relation to perinatal HIV transmission. As part of a multicenter perinatal HIV transmission study in an antenatal population with 2% HIV seroprevalence, endocervical swabs obtained at mid-pregnancy from a consecutive sample of 222 HIV-seropositive and 219 HIV-seronegative pregnant women at two large hospitals in Bangkok were tested for the presence of C. trachomatis and N. gonorrhoeae by DNA hybridization probe (Gen-Probe). Clinical risk factors and DNA probe results were analyzed in relation to the women&#39;s and newborns&#39; HIV infection status. The prevalence of C. trachomatis was 16.2% in HIV-seropositive pregnant women and 9.1% in HIV-seronegative pregnant women (P = 0.03). The prevalence of N. gonorrhoeae was 2.7% in HIV-seropositive pregnant women and 1.4% in HIV-seronegative pregnant women (P = 0.5). The overall population prevalence estimate was 9.2% for C. trachomatis and 1.4% for N. gonorrhoeae. Women with gonococcal infection were more likely to be positive for C. trachomatis (RR(MH) = 5.2, P &lt; 0.01). Young age (&lt;21 years) and primigravid status were associated with C. trachomatis infection among HIV-seropositive women; history of multiple sex partners (&gt;1) were associated with C. trachomatis infection among HIV-seronegative women. For HIV-seropositive women, primigravida status also was associated with C. trachomatis infection. The perinatal HIV transmission rates were similar for those with and without C. trachomatis (24.1% and 23.2%, P = 0.9) and among those with and without N. gonorrhoeae (20% and 23.5%, P = 1.0). Among pregnant women in Bangkok, C. trachomatis infection was considerably more common than N. gonorrhoeae infection and was associated with HIV infection, young age and first pregnancy (HIV-seropositive women), and multiple partners (HIV-seronegative women). Our data do not suggest an association between perinatal HIV transmission and maternal C. trachomatis or N. gonorrhoeae infection identified and treated during pregnancy. The high prevalence of C. trachomatis found using a test not readily available in Thailand emphasizes the need for improved, inexpensive ways to screen for and diagnose these sexually transmitted infections in developing countries.

Research paper thumbnail of Safety of Late In Utero Exposure to Zidovudine in Infants Born to Human Immunodeficiency Virus-Infected Mothers: Bangkok

PEDIATRICS, 2001

, for the Bangkok Collaborative Perinatal HIV Transmission Study Group ABSTRACT. Background. Shor... more , for the Bangkok Collaborative Perinatal HIV Transmission Study Group ABSTRACT. Background. Short-course zidovudine (ZDV) given in the late antenatal period can reduce mother-infant human immunodeficiency virus (HIV) transmission by one half. Because this intervention is being implemented in developing countries, evidence of its safety is needed. Methods. In a randomized, double-blinded, placebocontrolled trial in Bangkok, HIV-infected pregnant women received either ZDV (300 mg twice daily from 36 weeks' gestation until labor, then every 3 hours until delivery) or an identical placebo regimen. Infants were evaluated at birth and at 1, 2, 4, 6, 9, 12, 15, and 18 months of age. Growth, clinical events, and hematologic and immunologic measurements were compared between treatment groups. Results. Of the 395 children born (196 in ZDV group and 199 in placebo group), 330 were uninfected, 55 were infected, and 10 had indeterminate infection status. Overall, 319 children (81%) completed 18 months of follow-up, and 14 (4%) died before 18 months of age. Among uninfected children, the mean hematocrit was lower in the ZDV group at birth (49.1% vs 51.5%) but not at later ages; mean weight, height, head circumference, and CD4 ؉ and CD8 ؉ T lymphocyte counts were similar in both groups at all ages. Five uninfected children in the ZDV group but only one in the placebo group had a febrile convulsion. No other signs suggestive of mitochondrial dysfunction and no tumors were observed. Among infected children, an estimated 62% in the ZDV group and 77% in the placebo group survived free of Centers for Disease Control and Prevention class C disease during the 18-month follow-up. Conclusions. No significant adverse events were associated with short-course ZDV during 18 months of follow-up in this population.