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The serodiagnosis of human immunodeficiency virus type 1 (HIV-1) infection primarily relies on the detection of antibodies, most of which are directed against the immunodominant regions (IDR) of HIV-1 structural proteins. Among these, the N-terminal region of gp41 contains cluster I (amino acids [aa] 580 to 623), comprising the cytotoxic T-lymphocyte epitope (AVERYLKDQQLL) and the cysteine loop (CSGKLIC), and cluster II (aa 646 to 682), comprising an ectodomain region (ELDKWA). To delineate the epitope diversity within clusters I and II and to determine whether the diversity affects serologic detection by U.S. Food and Drug Administration (FDA)-licensed enzyme immunoassay (EIA) kits, gp41 Env sequences from 247 seropositive persons infected with HIV-1 group M, subtypes A ( n = 42), B ( n = 62), B′ ( n = 13), C ( n = 38), D ( n = 41), E ( n = 18), F ( n = 27), and G ( n = 6), and 6 HIV-1-infected but persistently seronegative (HIPS) persons were analyzed. While all IDR were highly conserved among both seropositive and HIPS persons, minor amino acid substitutions (n = 152) tested positive with all five FDA-licensed EIA kits. Furthermore, all specimens reacted with a group M consensus gp41 peptide (WGIKQLQARVLAVERYLKDQQLLGIWGCSGKLICTTAVPWNASW), and high degrees of cross-reactivity (>80%) were observed with an HIV-1 group N peptide, an HIV-1 group O peptide, and a peptide derived from the homologous region of gp41 from simian immunodeficiency virus from chimpanzee (SIVcpz). Taken together, these data indicate that the minor substitutions observed within the IDR of gp41 of HIV-1 group M subtypes do not affect antibody recognition and that all HIV-1-seropositive specimens containing the observed substitutions react with the FDA-licensed EIA kits regardless of viral genotype and geographic origin.

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 from 310 women and more frequently from a subset of 74 women. At 38 weeks, after a 2-week treatment period, CVL HIV-1 was quantifiable in 23% and 52% of samples in the zidovudine and placebo groups, respectively (P 10,000 copies/mL) and 1% among women without quantifiable CVL HIV-1 and with low plasma virus levels (P

To determine the rate and risk factors for human immunodeficiency virus (HIV)-1 subtype E perinatal transmission, with focus on virus load, pregnant HIV-infected women and their formula-fed infants were followed prospectively in Bangkok. Of 281 infants with known outcome, 68 were infected (transmission rate, 24.2%; 95% confidence interval, 19.3%-29.6%). Transmitting mothers had a 4.3-fold higher median plasma HIV RNA level at delivery than did nontransmitters (P 10,000 copies/mL. Although risk is multifactorial, high maternal virus load at delivery strongly predicts transmission. This may have important implications for interventions designed to reduce perinatal transmission.

Summary Background Many developing countries have not implemented the AIDS Clinical Trials Group 076 zidovudine regimen for prevention of perinatal HIV-1 transmission because of its complexity and cost. We investigated the safety and efficacy of short-course oral zidovudine administered during late pregnancy and labour. Methods In a randomised, double-blind, placebo-controlled trial, HIV-1-infected pregnant women at two Bangkok hospitals were randomly assigned placebo or one zidovudine 300 mg tablet twice daily from 36 weeks' gestation and every 3 h from onset of labour until delivery. Mothers were given infant formula and asked not to breastfeed. The main endpoint was babies' HIV-1-infection status, tested with HIV-1-DNA PCR at birth, 2 months, and 6 months. We measured maternal plasma viral concentrations by RNA PCR. Findings Between May, 1996, and December, 1997, 397 women were enrolled; 393 gave birth to 395 live-born babies. Median duration of antenatal treatment was 25 days, and median number of doses during labour was three. 99% of women took at least 90% of scheduled antenatal doses. Adverse events were similar in the study groups. Of 392 babies with at least one PCR test, 55 tested positive: 18 in the zidovudine group and 37 in the placebo group. The estimated transmission risks were 9·4% (95% CI 5·2–13·5) on zidovudine and 18·9% (13·2–24·2) on placebo (p=0·006; efficacy 50% [15·4–70·6]). Between enrolment and delivery, women in the zidovudine group had a mean decrease in viral load of 0·56 log. About 80% of the treatment effect was explained by lowered maternal viral concentrations at delivery. Interpretation A short course of twice-daily oral zidovudine was safe and well tolerated and, in the absence of breastfeeding, can lessen the risk for mother-to-child HIV-1 transmission by half. This regimen could prevent many HIV-1 infections during late pregnancy and labour in less-developed countries unable to implement the full 076 regimen.

s r s t e v p f s In a recent article, Dr. Scott raised ethical questions bout respondent-driven sampling, or RDS (Scott, 2008). r. Scott used data he collected in Chicago, Illinois in 2005 t the time that the National HIV Behavioural Surveillance ystem amongst injecting drug users (NHBS-IDU), sponored by the Centers for Disease Control and Prevention CDC), was being conducted. He asserted that RDS invites, f not promotes, violation of federal guidelines governing he protection of human research subjects and that the RDS esign generally, and the NHBS implementation specifially, resulted in data of questionable quality. CDC places he highest priority on human subjects protection and the thics of surveillance and research. We therefore comment n Dr. Scott’s article and then describe CDC plans for the ext NHBS-IDU cycle. Because NHBS uses a standard proocol in all sites (Lansky et al., 2007), we describe operations enerally, with details about the Chicago experience where elevant. Numerous controls for the protection of participants n research and surveillance activities are fundamental spects of the RDS method (Semaan, Santibanez, Garfein, eckathorn, & DesJarlais, 2008) and many were specifically sed in NHBS-IDU. The controls described below were put n place to assure the ethical conduct of NHBS-IDU. We isagree with Dr. Scott that “RDS assigns the lion’s share f responsibility for ethical conduct. . . to the human subjects

From May through August 1995, a cross-sectional survey was conducted among injecting drug users (IDUs) drawn from 15 drug treatment clinics in Bangkok and who were not known to be HIV-seropositive, to determine the prevalence of HIV-1 subtypes B and E and related risk behaviors, and to offer enrollment in a prospective cohort study. IDUs who voluntarily consented were interviewed, and blood specimens were tested for the presence of HIV antibodies. HIV-1-seropositive specimens were tested for subtypes B' (Thai B) and E by using V3 loop peptide enzyme immunoassays specific for these HIV-1 genetic subtypes. Of 1674 IDUs studied, the mean age was 31.2 years (interquartile range, 25-37 years), 94.8% were men, and 29.3% were HIV-1-seropositive. On multiple logistic regression analysis, HIV-1 seropositivity was associated with older age, not being married, less education, needle sharing, and incarceration. HIV-1 subtype B' accounted for 65% of prevalent infections and subtype E, 35%. Infection with subtype E was associated with younger age and did not seem to be associated with sexual risk behaviors, which were uncommon in general. Bangkok IDUs continue to be at high risk for HIV-1 infection related to needle sharing and incarceration. Although HIV-1 subtype B' accounts for most prevalent infections, subtype E seems to be more prevalent among younger IDUs, and most infections seem likely to result from parenteral transmission.In a 3-month period in 1995, voluntary HIV counseling and testing was offered to injecting drug users (IDUs) 20-50 years of age who attended any of the 15 drug treatment centers operated by the Bangkok (Thailand) Metropolitan Administration and were not known to be HIV-positive. The long-term purpose of this screening was to enroll a cohort in which to monitor HIV trends and obtain HIV-1 strains for genetic and phenotypic characterization. 1674 predominantly male IDUs (mean age, 31.2 years) were screened. 70.1% reported having been tested for HIV in the past 3 years. In the preceding 6 months, 77.9% had injected drugs at least once a day, 39.1% had used needles or syringes used by others, and 42.5% had shared needles. HIV-1 seroprevalence was 29.3%. In multiple logistic regression analysis, the following factors were significantly and independently associated with HIV-1 positivity: older age, unmarried status, less than 7 years of education, having shared needles or syringes, incarceration in the past 6 months, and drug injection during incarceration. A convenience sample of 205 of the 490 HIV-1-positive specimens was selected for serotyping through use of V3 loop peptide enzyme immunoassays. Of the 194 for which the HIV-1 subtype could be determined, 126 (64.9%) reacted to subtype B prime ("Thai B") and 68 (35.1%) reacted to subtype E. Subtype E was significantly more common among younger IDUs. 822 of the 1184 HIV-negative IDUs were interviewed and offered enrollment in the prospective cohort study; 678 (82.5%) agreed to participate. A phase III efficacy trial of an HIV-1 vaccine may be feasible in this cohort.

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.Findings are presented from a prospective study conducted to determine the rate of and risk factors for HIV-1 seroconversion, and to describe sexually transmitted diseases (STD) prevalence rates for young men in northern Thailand. Study findings are based upon data collected from self-administered questionnaires and serologic testing at enrollment in 1991 and at follow-up after 6, 17, and 23 months on a cohort of 1115 young men chosen by lottery for military conscription. Men in Thailand are generally eligible for conscription in the year of their 21st birthday. 6.9% of the men were HIV-1 seropositive at enrollment; 15.3% of men from the upper northern region compared with 2.5% of men from elsewhere. 14 subjects seroconverted to HIV-1 envelope subtype E over the course of the study. The overall HIV-1 incidence rate was 1.1/100 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. Multivariate analyses found frequent sex with female prostitutes, receptive anal sex, and high levels of alcohol consumption to be positively associated with HIV-1 seroconversion. 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 female prostitutes, and was generally higher for men from the upper north.

The objective of this study was to assess changes in the family situation of HIV-infected women who have recently given birth. As part of a prospective perinatal HIV transmission study, interviews were conducted with a subset of HIV-infected women at 18 to 24 months postpartum, and answers were compared with baseline information obtained during pregnancy. Standardized scales were used to assess levels of psychosocial functioning. A convenience sample of 129 HIV-infected women enrolled during pregnancy was interviewed at 18 to 24 months postpartum. At delivery, the women were young (median age, 22 years), primiparous (57%), and asymptomatic (93%). When baseline and follow-up data were compared, more women were living alone (1% versus 6%; p = 0.03), fewer women were living with their partners (98% versus 73%; p0.001), and 30% of families had reduced incomes. At follow-up, 10% of partners had died, and more partners than wives had become ill or died (21% versus 4%; p = 0.02). Most children (78%) were living with their mothers, but only 57% of the HIV-infected women were the primary caretakers. Fewer women had disclosed their HIV status to others (e.g., family, friends) than to their partners (34% versus 84%; p0.001), largely because of fear of disclosure. The women appeared to have high levels of depression and worry. The women's greatest worries were about their children's health and the family's future. Within 2 years after childbirth, substantial change within the families of HIV-infected women was evident. These were manifest by partner illness or death, family separation, reduced family income, shifting responsibilities for child care, and signs of depression and isolation. Providing family support is a major challenge in Thailand as the perinatal HIV epidemic progresses.As part of a larger prospective perinatal HIV transmission study in Bangkok, Thailand (1992-94), interviews were conducted with a subset of 129 HIV-infected women 18-24 months after delivery and the results were compared with data obtained from these women during pregnancy. The median age of women at delivery was 22 years; 57% were primiparous and 93% were asymptomatic at delivery. 25 infants (19.4%) had confirmed HIV infection and 2 had died by the time of the follow-up interview. By follow up, 21% of male partners had died or developed HIV-related functional impairments. The proportion of women living alone rose from 1% at baseline to 6% at follow up, while the proportion living with their partner declined from 98% to 73%. 30% of families had reduced incomes at follow-up compared with baseline. Although 78% of infants were living with their mothers, they were the primary caretakers in only 57% of families. Only 34% of HIV-infected mothers had disclosed their HIV status to friends or family other than their partner. 43% of women scored above the cut-off on the depression scale. Mothers worried extensively about their child's health and their family's future. However, only 37% believed they could find someone to talk to about their feelings related to HIV. 58% were interested in joining a support group for women with HIV. These findings of family disruption, reduced family income, shifting responsibilities for child care, depression, and isolation indicate an urgent need for increased social support for HIV-infected mothers in Thailand.

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.

Extensive transmission of human immunodeficiency virus type 1 (HIV-1) in Thailand began in 1988, resulting in an estimated 800,000 cumulative infections by 1994. During 1994 and 1995, we collected blood specimens from 215 asymptomatic HIV-1-infected people with various risk behaviors from nine locations in all four regions of Thailand. HIV-1 subtypes and genetic heterogeneity were determined for 214 strains by a combination of direct DNA sequencing (n = 95), subtype-specific oligonucleotide probe testing (n = 201), and V3-loop peptide enzyme immunoassay (PEIA) (n = 214). All strains were either env subtype E (175; 81.8%) or B (39; 18.2%). Of the subtype B isolates, 37 (94.9%) were B' and 2 (5.1%) were more typical North American-like B strains (most subtype B strains in Thailand are part of a distinct subcluster within the subtype B branch on phylogenetic trees, termed B'; formerly Thai B or BB). Of 149 viruses from people with sexual risk behaviors from all regions, 146 (98.0%) were subtype E. Of 65 viruses from injecting drug users (IDUs), 29 (44.6%) were subtype E and 36 (55.4%) were subtype B, including 35 B' strains. There was regional variation in the proportions of subtypes E and B' among IDUs. The intrasubtype nucleotide divergence within the V3 and flanking regions of the env gene (mid-C2 to the start of the V4 region) was low (5.7% for subtype E and 3.1% for subtype B') compared with other HIV-1 group M subtypes from different countries. These findings of two subtypes with low heterogeneity indicate that Thailand may be a desirable setting for evaluating candidate HIV-1 vaccines. The mix of subtype E and B' strains among IDUs also offers the opportunity to study phenotypic differences between the two subtypes.The extensive transmission of HIV-1 in Thailand which began in 1988 led to an estimated 800,000 cumulative infections in the country by 1994. The authors collected blood specimens during 1994 and 1995 from 215 asymptomatic HIV-1-infected people with various risk behaviors from 9 locations across Thailand. HIV-1 subtypes and genetic heterogeneity were then determined for 214 strains using a combination of direct DNA sequencing, subtype-specific oligonucleotide probe testing, and V3-loop peptide enzyme immunoassay. 175 strains were subtype E and 39 were subtype B. 37 of the subtype B isolates were B' and 2 were more typical North American-like B strains. Of 149 viruses from people with sexual risk behaviors from all regions of the country, 146 were subtype E. Of 65 viruses from IV drug users (IVDUs), 29 were subtype E and 36 were subtype B, including 35 subtype B' strains. Regional variation was observed in the proportions of subtypes E and B' among IVDUs. The intrasubtype nucleotide divergence within the V3 and flanking regions of the env gene was 5.7% for subtype E and 3.1% for subtype B'. The finding of 2 HIV-1 subtypes with low heterogeneity suggests that Thailand may be an appropriate setting in which to evaluate candidate HIV-1 vaccines. The mix of subtype E and B' strains among IVDUs will also allow the study of phenotypic differences between the 2 subtypes.

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's and newborns' 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, P0.01). Young age (21 years) and primigravid status were associated with C. trachomatis infection among HIV-seropositive women; history of multiple sex partners (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.Numerous studies have suggested that Chlamydia trachomatis and Neisseria gonorrhoeae facilitate heterosexual HIV transmission; the impact of these sexually transmitted diseases (STDs) on perinatal HIV transmission is unknown, however, due to the expense of routine screening for STDs during pregnancy in developing countries. As part of a multicenter perinatal HIV transmission study, 222 HIV-positive and 219 HIV-negative women presenting for prenatal care at 2 hospitals in Bangkok, Thailand, during 1993-94 were enrolled. At mid-pregnancy, endocervical swabs were obtained and tested for the presence of C. trachomatis and N. gonorrhoeae by DNA hybridization probe. There were 36 cases (16.2%) of C. trachomatis infection among HIV-positive women and 20 cases (9.1%) among HIV-negative women. There were 6 cases (2.7%) of N. gonorrhoeae among HIV-positive women and 3 cases (1.4%) among HIV-negative women. Based on an estimated antenatal HIV seroprevalence of 2%, these findings imply a general antenatal prevalence of 9.2% for C. trachomatis and 1.4% for N. gonorrhoeae. Women with gonococcal infection were more likely (relative risk, 5.2) to be positive for C. trachomatis as well. C. trachomatis infection among HIV-infected pregnant women was associated with age under 21 years and primigravidity. The overall perinatal HIV transmission rate was 24.2%, with no significant difference according to STD infection status. However, since all women diagnosed with STDs received treatment by the mid-third trimester of pregnancy, it remains possible that untreated STDs facilitate perinatal HIV transmission. The high prevalence of C. trachomatis detected in this study through use of a test not readily available in Thailand emphasizes the need for inexpensive, reliable methods to screen for STDs among pregnant women in developing countries.

The epidemic of Human Immunodeficiency Virus (HIV) infection led blood banks to initiate donation deferral criteria based on self-reported risk factors. However little information is available on the differences in reporting risk factors before and after HIV status is known.Between April and July 1994, blood donors in a provincial hospital in northern. Thailand were interviewed at the time of donation, about their demographic characteristics and risk factors. All donors had agreed to learn their test results and were called back for post-test counselling and reinterview.HIV-positive blood donors were more likely to change from 'denying' to 'acknowledging' risk factors while HIV-negatives were more likely to change from 'acknowledging' to 'denying'. The differences between risk factors obtained before and after test results were known resulted in stronger, weaker or even opposite risk measures.The study results raise questions about the impact of the differences in reporting HIV-related risk factors by the donors on how effective donation deferral criteria can be developed.The widespread prevalence of HIV infection in countries and regions around the world has led blood banks to refuse blood donations from donors who are at high risk of being infected with HIV. Low-risk donors are instead recruited and all donors are tested for infection with HIV. The criteria for donor deferral are based mainly upon the epidemiology of HIV infection among the donors. The authors investigated the differences in reporting risk factors before and after HIV status is known. During April-July 1994, blood donors at a hospital in Chiangrai province were interviewed at the time of donation about their demographic characteristics and risk factors. 134 of the 175 HIV-positive donors returned for post-HIV-test counseling and reinterview. 423 of the 1062 HIV-negative donors returned. The donors were of median age 32 years. HIV-positive donors were more likely to change from denying to acknowledging risk factors, while HIV-seronegative donors were more likely to change from acknowledging to denying. The differences between risk factors observed before and after test results were known resulted in stronger, weaker, or even opposite risk measures.

Eight sera from culturally-proven cases of penicilliosis marneffei and their corresponding isolates were examined for circulating antibody(ies) and antigen, and exoantigens, respectively, using a microimmunodiffusion (MID) test. Two of the 8 sera produced strong precipitins (1-2) when reacted against control Penicillium marneffei antigen (5-week-old shaken cultures at 25 C) in the presence of control rabbit anti-P. marneffei serum. Five of the 8 sera produced a strong precipitin line when reacted against control hyperimmune serum to P. marneffei. These five sera, and one additional serum, which tested negative for antibody to P. marneffei, demonstrated the presence of antigen by reacting only against the anti-P. marneffei serum. Serological evaluations of the sera revealed that the MID test is capable of detecting antibody and antigen in AIDS patients having penicilliosis marneffei infections. Exoantigen analysis of the 8 P. marneffei isolates, which were previously identified using the conventional and time-consuming macro- and micro-morphological characteristics, showed the presence of 1 to 4 specific exoantigens in MID. With the exoantigen analysis, the identity of all of the isolates was confirmed as P. marneffei. Our studies indicated that the serological tests are useful for detecting circulating antibody and/or antigen in patients' sera, and that the exoantigen test is reliable for confirming the identity of P. marneffei cultures.

Initial research on the genetic variability of human immunodeficiency virus (HIV)-1 has indicated that HIV-1 envelope subtype B is dominant in Western countries where homosexuality and injecting drug use are the major risk factors while env subtypes A C D and E predominate in Africa and Asia where most transmission is heterosexual. Data from South Africa and Thailand suggest that due to limited mixing of population subgroups largely independent HIV epidemics caused by different genotypic subgroups may co-exist in a given geographic area. On the other hand the possibility that HIV-1 subtypes differ in transmission efficiency by exposure mode also has some support. For example subtypes E and C appear to be better adapted to penile-vaginal transmission while subtypes B E and C may be transmitted efficiently through blood. Factors such as sexual mixing patterns (e.g. commercial sex work) and the prevalence of sexually transmitted diseases must also be considered when examining HIV-1 subtype transmission differences. The use of new assays that allow for the accurate measurement of viral levels in plasma semen and genital secretions should complement epidemiologic estimates of transmission efficiency for various HIV-1 subtypes.

Structured interviews and focus group discussions were conducted among 834 young Thai men drafted into military service by random lottery in northern Thailand. Level of AIDS risk, exposure to AIDS information, level of knowledge about AIDS, and perception of risk for acquiring HIV and AIDS were assessed at baseline and six months after induction into the Army in 1991. General fear of AIDS was high, yet personal perception of risk for acquiring HIV was low, even for those at enhanced behavioural risk of infection with HIV. Multivariate PATH analysis shows that exposure to information about AIDS significantly reduced risk taking from baseline to follow-up, but only by first affecting personal risk perception. Focus group discussions revealed that risk perception for acquiring AIDS was low due to never knowing a person with AIDS, because prostitutes had health certificates for STD, and since many believed that AIDS could be cured or prevented with folk medicines. Implications and recommendations for intervention programmes are discussed.

This study sought to evaluate the sensitivity and specificity of peptide-binding enzyme immunoassay (PEIA) and heteroduplex mobility assay (HMA) for the determination of HIV-1 subtypes B and E; to determine the proportions of infections due to subtypes B and E over time; and to generate data on DNA sequences of the C2-V3 region of the env genes. HIV-1 subtyping was conducted by PEIA and HMA on blood specimens obtained from 97 injecting drug users (IDU) infected with HIV between 1988 and 1993. Genetic sequencing was performed on 84 specimens. Both laboratory methods were highly sensitive and specific for the determination of HIV-1 subtypes B and E. The two tests were complementary; samples which could not be typed by HMA were correctly typed by PEIA and vice versa. While subtype B accounted for 80.4% (78 out of 97) of infections overall the proportion of new infections due to subtype E increased from 2.6% (1 out of 38) in 1988-1989 to 25.6% (11 out of 43) in 1990-1991 and to 43.8% (7 out of 16) in 1992-1993 (chi squared for linear trend p < 0.001). HMA and PEIA are practical sensitive and specific laboratory methods for the determination of HIV-1 subtypes in Thailand and may be useful in other geographic areas to define the molecular epidemiology of the global HIV-1 pandemic. Data suggest that the proportion subtype E infections have increased among Bangkok IDU from 1988 through 1993. (authors)

Background: Preexposure prophylaxis with antiretroviral drugs has been effective in the prevention of human immunodeficiency virus (HIV) infection in some trials but not in others. Methods In this randomized, double-blind, placebo-controlled trial, we assigned 2120 HIV-negative women in Kenya, South Africa, and Tanzania to receive either a combination of tenofovir disoproxil fumarate and emtricitabine (TDF-FTC) or placebo once daily. The primary objective was to assess the effectiveness of TDF-FTC in preventing HIV acquisition and to evaluate safety. Results: HIV infections occurred in 33 women in the TDF-FTC group (incidence rate, 4.7 per 100 person-years) and in 35 in the placebo group (incidence rate, 5.0 per 100 person-years), for an estimated hazard ratio in the TDF-FTC group of 0.94 (95% confidence interval, 0.59 to 1.52; P=0.81). The proportions of women with nausea, vomiting, or elevated alanine aminotransferase levels were significantly higher in the TDF-FTC group (P=0.04, P

We have entered a new era in which antiretroviral agents have been demonstrated to be highly effective in preventing HIV-1 infection, especially in serodiscordant couples. The HPTN-052 randomized, controlled trial (RCT) of early versus delayed antiretroviral therapy (ART) for the HIV-1-infected persons in sexual partnerships with HIV-negative persons demonstrated at least a 96% reduction in HIV-1 transmission in the 1763 couples studied in Africa, Asia and South America [1]. The Partners PrEP RCT, conducted among 4758 HIV-1serodiscordant couples in Kenya and Uganda, showed that when used as preexposure prophylaxis (PrEP) by the HIV-negative partner, daily tenofovir disproxil fumerate (TDF) and daily TDF/emtricitabine (FTC) were 62 and 73% effective, respectively, in preventing HIV-1 acquisition [2]. These robust effectiveness findings provide a strong basis for the use of antiretroviral agents for prevention, both to reduce the infectiousness of HIV-1infected persons and to reduce the susceptibility of HIVnegative persons.

Background Project Accept is a community randomized, controlled trial to evaluate the efficacy of community mobilization, mobile testing, same-day results, and post-test support for the prevention of HIV infection in Thailand, Tanzania, Zimbabwe, and South Africa. We evaluated the accuracy of in-country HIV rapid testing and determined HIV prevalence in the Project Accept pilot study. Methods Two HIV rapid tests were performed in parallel in local laboratories. If the first two rapid tests were discordant (one reactive, one non-reactive), a third HIV rapid test or enzyme immunoassay was performed. Samples were designated HIV NEG if the first two tests were non-reactive, HIV DISC if the first two tests were discordant, and HIV POS if the first two tests were reactive. Samples were re-analyzed in the United States using a panel of laboratory tests. Results HIV infection status was correctly determined based on-in country testing for 2,236 (99.5%) of 2,247 participants [7 (0.37%) of 1,907 HIV NEG samples were HIV-positive; 2 (0.63%) of 317 HIV POS samples were HIV-negative; 2 (8.3%) of 24 HIV DISC samples were incorrectly identified as HIV-positive based on the in-country tie-breaker test]. HIV prevalence was: Thailand: 0.6%, Tanzania: 5.0%, Zimbabwe 14.7%, Soweto South Africa: 19.4%, Vulindlela, South Africa: 24.4%, (overall prevalence: 14.4%). Conclusions In-country testing based on two HIV rapid tests correctly identified the HIV infection status for 99.5% of study participants; most participants with discordant HIV rapid tests were not infected. HIV prevalence varied considerably across the study sites (range: 0.6% to 24.4%). Trial Registration ClinicalTrials.gov registry number NCT00203749.

In April 2007, the Centers for Disease Control and Prevention (CDC) held a two-day consultation with a broad spectrum of stakeholders to obtain input on the potential role of male circumcision (MC) in preventing transmission of human immunodeficiency virus (HIV) in the U.S. Working groups summarized data and discussed issues about the use of MC for prevention of HIV and other sexually transmitted infections among men who have sex with women, men who have sex with men (MSM), and newborn males. Consultants suggested that ( 1) sufficient evidence exists to propose that heterosexually active males be informed about the significant but partial efficacy of MC in reducing risk for HIV acquisition and be provided with affordable access to voluntary, high-quality surgical and risk-reduction counseling services; ( 2) information about the potential health benefits and risks of MC should be presented to parents considering infant circumcision, and financial barriers to accessing MC should be removed; and ( 3) insufficient data exist about the impact (if any) of MC on HIV acquisition by MSM, and additional research is warranted. If MC is recommended as a public health method, information will be required on its acceptability and uptake. Especially critical will be efforts to understand how to develop effective, culturally appropriate public health messages to mitigate increases in sexual risk behavior among men, both those already circumcised and those who may elect MC to reduce their risk of acquiring HIV.

More than half a million Americans became newly infected with human immunodeficiency virus (HIV) in the first decade of the new millennium. The domestic epidemic has had the heaviest impact on men who have sex with men and persons from racial and ethnic minority populations, particularly black persons. For example, black men who have sex with men represent

Guidelines for the prevention of nosocomial pneumonia specify that only sterile fluids should be used for aerosol therapy; however, this recommendation may not be uniformly followed. Thirteen patients with nosocomial pneumonia due to Legionella pneumophila serogroup 3 (Lp3) were identified at a community hospital in the period from 1984 through 1988; 12 patients (92%) had chronic obstructive pulmonary disease; and 9 patients (69%) died. An epidemiologic investigation suggested that the use of nebulizers to deliver medication was associated with acquiring legionnaires' disease. The hospital potable water system was contaminated with Lp3, and a survey indicated that tap water was commonly used to wash medication nebulizers. Lp3 in respirable-size droplets was isolated from aerosols generated by a nebulizer containing Lp3 at one-tenth the concentration found in the hospital potable water. These findings support the recommendation that only sterile fluids be used for filling or cleaning respiratory care equipment and suggest that this guideline is not universally followed.

87 strains of Streptococcus pneumoniae isolated during three winter seasons (1986-89) from the blood of children with acute lower respiratory tract infection (ALRI) in Pakistan were serotyped and tested for susceptibility to a range of antimicrobial agents. 97% of isolates were resistant to at least one antimicrobial drug. 62% had decreased susceptibility to co-trimoxazole (trimethoprim/ sulphamethoxazole) (31% were fully resistant) and 39% were resistant to chloramphenicol. All isolates were susceptible to erythromycin, cefaclor, cephalothin, ceftriaxone, cefuroxime, rifampicin, vancomycin, and clindamycin. 29% of isolates were neither vaccine types nor vaccine-related types. Serotype distribution and antimicrobial susceptibility varied significantly during the three winter seasons. No single serotype was found in all three winters. The findings highlight the need for surveillance of antimicrobial resistance and serotype distribution of S pneumoniae in developing countries as a guide both to the choice of agent for treatment of pneumococcal infections, especially ALRI, and to the formulation of new pneumococcal conjugate vaccines for use in young children.

GROUP A β-hemolytic streptococcus is an uncommon but serious cause of postoperative wound infection. Group A streptococcus is isolated from less than 1 percent of all surgical-wound infections and causes less than 1 incisional-wound infection per 10,000 operations (National Nosocomial Infections Surveillance System, Centers for Disease Control: unpublished data). Clusters of group A streptococcal postoperative wound infections can usually he associated with a carrier who has direct patient-care responsibilities in the operating room. A carrier was identified in 10 of the 12 outbreaks reported since 1965.1 2 3 4 5 6 7 8 9 10 11 12 13 Eight carriers were operating-room personnel with group A streptococcus in their rectums or vaginas. . . .

Epidemiologic studies have suggested that legionnaires' disease can be transmitted to susceptible hosts by contaminated aerosolized water from cooling towers and evaporative condensers; however, epidemic strains of Legionella have not been isolated by air sampling at such sites during epidemiologic investigations. An outbreak of legionnaires' disease occurred at a retirement hotel; Legionella pneumophila serogroup 1 was isolated from an evaporative condenser and from potable water. A case-control study showed that the only significant exposure risk was in area A. L. pneumophila serogroup 1 was isolated during air sampling near the evaporative condenser exhaust site, the air conditioning intake vent, and an air vent in area A, but not in shower stalls. Monoclonal antibody subtype patterns of L. pneumophila serogroup 1 isolates from patients matched those from the evaporative condenser but not from shower water. Air sampling and monoclonal antibody subtyping results support epidemiologic evidence that the evaporative condenser was the source of this outbreak.

Recent clinical trials in Africa found that male circumcision reduces the risk of acquiring HIV from heterosexual sex--what are the implications of these studies for the United States?

In northern Thailand, where substantial male-to-female transmission of HIV has occurred in stable partnerships, the relationships between counseling, communication, and HIV-preventive behaviors in married couples have not been well studied. In a study of HIV incidence among women in northern Thailand, each participant was advised to learn her husband's HIV-infection status and was asked to bring him for an interview at the final 12-month follow-up visit. Of the 337 men interviewed, 58% reported having ever had an HIV test. More men reported testing following their wives' enrollment: 12% in the year prior to enrollment vs 22% during the 1-year study (p0.001). In the univariate analysis, men's HIV testing during the 6 months before being interviewed was associated with communication about HIV testing with their wife and extra marital sex with non-FSW while married. Testing following their wife's request was the most common reason reported. Agreement between husband's and wife's reports was poor for most issues, such as whether HIV-related communication had occurred, but agreement as to whether the husband had ever been tested for HIV was relatively high (kappa = 0.62). However, in the logistic regression analysis, only sex with non-FSW while married remained associated with HIV testing (p = 0.02). The results suggest a relationship between counseling, communication, and husband HIV testing. Better communication by couples may result in more effective use of HIV testing, which is already prevalent in this population, to prevent HIV transmission.

The objective was to determine the safety and acceptability of vaginal application of Carraguard a carrageenan-derived candidate microbicide gel. A randomized placebo-controlled triple-blinded clinical trial was conducted in Chiang Rai northern Thailand. Women were asked to insert one applicator of study gel vaginally at least three times per week (with or without sex) and to use gel with condoms every time they had sex. Safety was assessed by visual inspection of the vagina and cervix changes in vaginal flora and self-reported symptoms at day 14 month 1 and then monthly for up to 1 year. Acceptability was assessed through reported use of the gel return of used and unused applicators and quarterly interviews. One hundred sixty-five women were randomized: 83 to Carraguard and 82 to the placebo (methylcellulose gel) group. Study gel use was similarly high in both groups throughout the trial with an average of four applicators per week. Carraguard use was not associated with abnormal genital clinical findings abnormal vaginal flora Pap smear abnormalities or other abnormal clinical signs or symptoms. Adverse events were mostly mild not attributed to gel use and similarly distributed between groups. Participants in both groups reported high acceptability. Carraguard can safely be used an average of four times per week with or without sex and is acceptable to Thai women. A Phase III efficacy trial of Carraguard is warranted and is currently ongoing in South Africa. (authors)

Some candidate HIV-1 vaccines may not prevent HIV-1 infection but may alter the course of disease. Surrogate endpoints based on early laboratory makers in HIV-1-infected persons who are antiretroviral therapy (ART)-naive will be useful for evaluating vaccine efficacy in slowing disease progression (VEp). We examined pretreatment HIV-1 viral loads and CD4 cell counts in recent HIV-1 seroconverters to inform selection of these endpoints.We studied 130 newly HIV-1-infected injection drug users identified from a prospective cohort of initially uninfected persons in Bangkok during 1995 through 1998. We analyzed trends in HIV-1 viral loads and CD4 cell counts as well as progression to the surrogate endpoint, defined as 2 consecutive CD4 cell counts of fewer than 350 cells/mm, during 24 months after the first HIV-1 seropositive (FP) visit.Median HIV-1 RNA copies/mL with interquartile ranges were 43,693 (14,320-94,767) at the FP visit, 46,924 (16,273-104,314) at 6 months, 28,446 (11,292-54,325) at 12 months, and 18,080 (8713-54,059) at 18 months. HIV-1 viral loads at the FP visit and at 18 months were positively correlated (r = 0.53, P0.0001). Of 130 participants, 12% reached the surrogate endpoint by 6 months, 16% by 12 months, and 27% by 18 months. In Cox regression analyses, HIV-1 viral loads of more than 50,000 copies/mL at the FP visit (hazard ratio [HR] = 2.3, 95% confidence interval [CI]: 1.1-4.8) and first CD4 cell count of 500 or fewer cells/mm (HR = 7.6, 95% CI: 3.2-17.6) were independently associated with faster progression to the surrogate endpoint.Participants with high HIV-1 RNA levels and low CD4 cell counts close to the time of seroconversion were more likely to experience early immunologic progression. Approximately one quarter of seroconverters reached the surrogate immunologic endpoint within 18 months of their FP visit and before starting ART, suggesting the utility of this endpoint for analyses of VEp in some ongoing and planned HIV-1 vaccine efficacy trials.

Homo- or bisexual (HB) adolescents may have greater and different health risks than the population of heterosexual adolescents. We assessed sexual orientation and health risk behaviors in 1,725 consenting 15- to 21-year-old vocational school students in northern Thailand. Data were collected using audio-computer-assisted self-interviewing. Nine percent of males and 11.2% of females identified themselves as homo- or bisexual. HB males had an earlier mean age at sexual debut (14.7 years) and a higher mean number of lifetime sexual partners (7.9) than did heterosexual males (16.8 years and 5.8 partners, respectively). HB males (25.9%) and females (32.2%) were sexually coerced more often than were heterosexual males (4.6%) and females (19.6%). Drug use was reported significantly more frequently by HB females and significantly less frequently by HB males than by their heterosexual counterparts. HB males showed more signs of social isolation and depression than did heterosexual males. We conclude that HB adolescents in northern Thailand are at greater and different health risks than are their heterosexual counterparts. Differential health education messages for HB and heterosexual youth are warranted.

The leukocytes of rhesus monkeys contain cyclic octadecapeptides (theta;-defensins) that can protect cells from infection by HIV-1 in vitro. Although humans express mRNA from one or more theta;-defensin pseudogenes, these transcripts contain a premature stop codon that prevents formation of theta;-defensin peptides. We hypothesized that some highly exposed persistently seronegative (HEPS) individuals might have intact theta;-defensin (DEFT) genes and produce functional theta;-defensins that might account for their resistance to HIV-1 infection. We sequenced DEFT genes from 30 women in Chiang Rai, northern Thailand: 11 HEPS female sex-workers and 19 control women (10 HIV-1 infected and 9 HIV-1 uninfected). We found that theta;-defensin genes from all 11 HEPS women contained the crucial signal sequence stop codon, as did the 19 control women. Synthetic theta;-defensins based on the cDNA sequences to generate a human theta;-defensin (termed retrocyclin-1 and -2) were capable of inhibiting replication of Thai HIV-1 subtype B and CRF01_AE isolates regardless of the coreceptor utilization of the isolates. Although our study indicates that synthetic theta;-defensin peptides are effective in vitro against Thai subtype B and CRF01_AE isolates of HIV-1, the presence of premature stop codons in the DEFT genes of these HEPS women makes it unlikely that endogenous theta;-defensin production accounts for their resistance to HIV-1.

This chapter emphasizes the global molecular epidemiology of human immunodeficiency virus (HIV) including an overview of its genetic diversity and related implications. Advances in molecular biology, immunology, and epidemiology have contributed greatly to the understanding of HIV. HIV is a primate retrovirus that shares the ability to infect their host chronically and progressively damage the host's immune system. Genetic variation of HIV is extremely high as a consequence of the rapid turnover of HIV virions. Individuals infected with HIV maintain a substantial viral burden during the entire course of infection. Related strains share genetic similarity, as expressed by the sequence of component nucleotides and methods have been developed to infer the phylogenetic relationships among different strains. Furthermore, at present, data regarding HIV subtypes is mostly limited to studies conducted for purposes other than surveillance. The expansion of epidemiologic surveillance for different strains of HIV and attempts to collect representative specimens from different populations can provide useful information to the public health community on the danger of emerging infectious agents such as HIV.

In 1990, a joint activity between the Thailand Ministry of Public Health (MoPH) and the U.S. Centers for Disease Control and Prevention (U.S. CDC) known as the “HIV/AIDS Collaboration” was born, its primary objective was to conduct HIV prevention research to contribute to HIV/AIDS control efforts in Thailand. The Collaboration maintained an office and a laboratory on the campus of the MoPH in Nonthaburi, a Bangkok suburb. U.S. CDC scientists and public health advisors were assigned to live and work in Thailand alongside Thai MoPH colleagues. Local staff were hired and supported by the U.S. Embassy in Bangkok and the MoPH. This research initiative built on the trust established between the Thai MoPH and the U.S. CDC through the Thai Field Epidemiology Training Program (FETP), which was inaugurated in 1980, becoming the first FETP program outside North America. The Thai FETP is modeled on U.S. CDC’s Epidemic Intelligence Service (EIS) program, both striving to improve public health surveillance, prevention and disease control efforts.

This chapter describes obstacles hindering the development of a preventive human immunodeficiency virus (HIV) vaccine, progress toward developing and evaluating vaccine candidates, clinical trials, the social and ethical issues involved in conducting HIV vaccine trials, and plans for future efficacy trials. Three obstacles are widely considered responsible for hindering the development of an HIV-1 vaccine. These obstacles are the extensive antigenic variability of HIV, uncertainty regarding which immune responses are correlated with protection, and the lack of an ideal animal model on which to test vaccine constructs. Despite the difficulties involved in developing an HIV vaccine, more than 80 vaccine constructs have proceeded to human clinical trials and one of two large-scale efficacy trials has been completed, with the second scheduled for completion by late 2003. Furthermore, there is an increasing awareness among trial investigators regarding the ethical and social obligations to protect trial participants' rights and provide important human rights protections.

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.

The goals of this study were to identify and characterize recombinant human immunodeficiency virus type 1 (HIV-1) genomes among incident infections in a prospective cohort study of injecting drug users (IDUs) in Bangkok, Thailand. Through cross-sectional, comparative phylogenetic analysis of the protease and env (C2-V4) gene regions, subtype discordance was observed in HIV-1 sequences from 4 of 111 IDUs (3.5%). Near-full-length HIV-1 genome sequences of the four strains revealed that in all four, the gp120 sequences clustered with a CRF01_AE prototype, while the remainder of the genomes displayed distinct mosaic patterns, with multiple breakpoints between HIV-1 CRF01_AE and subtype B-like regions. Two of the four HIV-1 recombinant strains displayed a nearly identical mosaic structure, suggesting the possible emergence and spread of a potentially new circulating recombinant form of HIV-1. Further characterization of these and other recombinant genomes through long-term follow-up will be important in understanding the generation of viral diversity and escape from the hosts immune responses. This information will be especially important for vaccine development.

Resistance to HIV-1 infection despite repeated exposures has been associated with one or more HIV-specific responses, enhanced nonspecific immune modifications, and/or host genetic polymorphisms in certain individuals (highly exposed, persistently seronegative, HEPS). In the present investigation, we focused on the CCR5 gene polymorphisms and the association of such mutations to resistance to HIV-1 infection among 12 HEPS women in Chiang Rai, northern Thailand, and compared our findings with data from 10 HIV-1-infected and 9 HIV-1-uninfected unexposed women from the same geographic area. Although we have previously shown that none of the Thai women carried the Delta32 mutation, further analysis of the CCR5 coding gene region revealed that none of the women had other mutations that affect coreceptor activity (C101X or FS299) or chemokine responses (C20S, A29S, L55Q, C178R). Analysis of the CCR5 promoter region revealed that the CCR5 haplogroup C (HHC; 60%) was the predominant haplogroup among these women. Comparative analysis of the frequencies of different haplogroups among the three groups did not reveal any statistically significant differences (p0.05). However, we did find that two individuals from the HEPS group were homozygous for HHF*2 (the CCR2b- 64I bearing haplogroup) compared to none from the HIV-1-infected and -uninfected groups. There was no detectable difference in specific CCR5 haplogroups and their ability to mediate env fusion or to mediate HIV-1 infection in vitro. These data suggest that homozygosity of the HHF*2 haplogroup may be one of the factors that mediate resistance to HIV-1 infection in this cohort of HEPS women.

The performance of the bioMérieux Vironostika-LS EIA (less sensitive enzyme immunoassay) was assessed to detect recent seroconversion among injecting drug users (IDUs) in Bangkok, Thailand who were infected with either HIV-1 subtypes B' or E (also known as circulating recombinant form CRF01_AE). To evaluate the Vironostika-LS EIA in non-B subtypes, we collected longitudinal specimens (n = 796) from 115 IDUs (subtype B' infection, n = 24; subtype E infection, n = 91). After testing HIV-positive specimens with the Vironostika-LS EIA, standardized optical densities (SODs) were calculated using median values to determine the window period, which is the time from seroconversion on a standard EIA to seroconversion on the Vironostika-LS EIA for a given SOD, for either subtype. For an SOD cutoff of 1.0, Vironostika-LS EIA results showed a mean window period of 239 days (95% confidence interval [95% CI], 208-287 days) for subtype B' and 356 days (95% CI, 318-402 days) for subtype E in Thailand. This outcome demonstrates that the Vironostika-LS EIA has significantly different performance characteristics in detecting recent seroconversion between different HIV-1 subtypes. Accurate identification of recent infection and estimation of incidence for HIV-1 strains other than North American subtype B, using the Vironostika-LS EIA, requires knowledge of specimen subtype and use of appropriate cutoffs and mean window periods.

To investigate knowledge and perceptions of HIV transmission risk and interest in vaginal microbicides in northern Thailand, we conducted 14 focus group discussions and 80 interviews with men and women in Chiang Rai province. Women were recruited from antenatal or postpartum clinics, and men from various work sites. Participants evinced substantial knowledge about HIV, with two exceptions important for prevention campaigns: (a) confusion about the window period between a new infection and positive HIV-test result and (b) overestimation of the safety of extramarital sex with partners who are not sex workers. Most participants reported no personal HIV risk. Participants described Thai women as generally vulnerable to HIV infection because of the unlikelihood of condom use with their husbands and because women cannot control their husbands' extramarital behavior. Women apparently face particular risk after childbearing; peripartum abstinence averages 6-9 months, during which time some Thai men may have alternative sex partners. Women, and to a lesser degree, men were interested in potential microbicides, although they voiced many thoughtful questions about the products and about efficacy trials.

Delineating factors associated with extrapulmonary cryptococcosis (EPC), a major disease burden among Thailand's AIDS patients, can clarify its pathogenesis and guide preventive interventions. From November 1993 through June 1996, enhanced surveillance of 2261 human immunodeficiency virus (HIV)-seropositive patients in a hospital near Bangkok showed EPC among 561 of 1553 AIDS patients (36.1%). Univariate analysis results were confirmed by multivariate analyses of data on 1259 patients. Logistic regression models identified factors significantly associated with EPC to be male sex (adjusted odds ratio [aOR], 2.0; 95% confidence interval [CI], 1.3-2.9), age33 years (aOR, 1.5; 95% CI, 1.2-1.9), severe immunosuppression (aOR, 1.8; 95% CI, 1.3-2.6), not injecting drugs (aOR, 3.0; 95% CI, 1.7-5.5), and infection with HIV-1 circulating from CRF01_AE (formerly subtype E) versus subtype B (aOR, 2.3; 95% CI, 1.2-4.5). The association with CRF01_AE may result from undetermined markers of exposure or viral subtype effects on host immune responses. Better understanding of the epidemiology of EPC may reduce EPC incidence through targeted primary prevention and treatment.

A safe, effective, and affordable vaccine remains the best long-term hope for bringing the global human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic under control. Recent scientific developments have suggested that the first generation of HIV vaccines available for public health care use will likely be of low to moderate efficacy, compared with currently licensed vaccines for other diseases. Nevertheless, such "partially effective" HIV vaccines could provide considerable individual and public health benefits. A consultation was held in January 2002 to advise the Centers for Disease Control and Prevention (Atlanta, Georgia) about critical issues that need to be addressed in anticipation of the eventual licensure and availability of an HIV vaccine in the United States. The present article summarizes the major issues discussed at the consultation with regard to the potential use of a partially effective vaccine in HIV prevention programs in the United States and the activities that are needed to prepare for vaccine availability.

Objective. To describe survival and signs of human immunodeficiency virus (HIV) infection in perinatally infected children in Thailand.Methods. At 2 large Bangkok hospitals, 295 infants born to HIV-infected mothers were enrolled at birth from November 1992 through September 1994 and followed up with clinical and laboratory evaluations every 1 to 3 months for 18 months. Infected children remained in follow-up thereafter. For the infected children, we used data collected through October 2000 to estimate survival times and compare characteristics among those whose disease progressed at rapid (died within 1 year), intermediate (died at 1–5 years), and slow (survived at least 5 years) rates.Results. None of the 213 uninfected children died during the follow-up period. Of the 68 infected children, 31 (46%) died; median survival was 60 months (95% confidence interval: 31–89 months). The most common cause of death was pneumonia (52% of deaths). Thirty-two children (47%) started antiretroviral therapy. Six children died in their first year before developing specific signs of HIV infection; all others developed signs of HIV infection between 1 and 42 months old (median: 4 months). Severe clinical (Centers for Disease Control and Prevention Class C) conditions were diagnosed in 23 children at a median age of 12 months, 15 (65%) of whom died a median of 3 months later. Compared with children whose disease progressed slowly, those whose disease progressed rapidly gained less weight by 4 months old (median 1.7 vs 2.6 kg), and their mothers had higher viral loads (median 5.1 vs 4.5 log10 copies/mL) and lower CD4+ counts (median 350 vs 470 cells/μL) at delivery.Conclusions. Among HIV-infected Thai children, survival times are longer than among children in many African countries, but shorter than among children in the United States and Europe. Signs of HIV develop early in most children. Growth failure and advanced maternal disease can predict rapid HIV disease progression and may be useful markers for treatment decisions.

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.