Incidence and predictors of regimen-modification from first-line antiretroviral therapy in Thailand: a cohort study.

BACKGROUND: Antiretroviral therapy markedly reduced mortality in HIV-infected individuals. However, in the previous studies, up to 50% of patients are compelled to modify their regimen in middle and low-income countries where salvage drug is still limited. This cohort study aimed to investigate the incidence and predictors of regimen modification from the first-line antiretroviral regimen in northern Thailand. METHODS: All HIV-infected patients starting antiretroviral therapy (ART) with generic drug (GPOvir®; stavudine, lamivudine and nevirapine) at a governmental hospital in northern Thailand from 2002 to 2007 were recruited. Baseline characteristics and detailed information of regimen modification until the end of 2010 were ascertained from cohort database and medical charts. As a potential genetic predictor of regimen modification, HLA B allele was determined by bead-based array hybridization (WAKFlow® HLA typing kit). We investigated predictors of the regimen modification using Cox's proportional hazard models. RESULTS: Of 979 patients, 914 were eligible for the analysis. The observed events of regimen modification was 377, corresponding to an incidence 13.8/100 person-year-observation (95% CI:12.5-15.3) over 2,728 person years (PY) follow up. The main reasons for regimen modification were adverse effects (73.5%), especially lipodystrophy (63.2%) followed by rash (17.7%). Sixty three patients (17.1%) changed the regimen due to treatment failure. 2% and 19% of patients had HLA-B*35:05 and B*4001, respectively. HLA-B*35:05 was independently associated with rash-related regimen modification (aHR 7.73, 95% CI:3.16-18.9) while female gender was associated with lipodystrophy (aHR 2.11, 95% CI:1.51-2.95). Female gender (aHR 0.54, 95% CI: 0.30-0.96), elder age (aHR 0.56, 95% CI: 0.32-0.99) and having HLA-B*40:01 (aHR 0.29, 95% CI: 0.10-0.82) were protective for treatment failure related modification. CONCLUSION: HLA-B*35:05 and female gender were strong predictors of regimen modification due to rash and lipodystrophy, respectively. Female gender, elder age, and having HLA-B*40:01 had protective effects on treatment failure-related regimen modification. This study provides further information of regimen modification for future tailored ART in Asia.

Changing burden of HIV/AIDS to clinical settings in Northern Thailand over 15 years.

We conducted a hospital-based descriptive study to describe the changing pattern of patient numbers, characteristics, and mortality rates among human immunodeficiency virus (HIV)-infected patients in northern Thailand over 15 years. The survival status on October 31, 2010 of all HIV-infected adults who attended an HIV center in a government hospital between 1995 and 2010 was ascertained. In total, 3,706 patients were registered, 2,118 (57.2%) of which were male. The survival status of 3,439 patients (92.9%) was available. In addition, 1,543 deaths were identified out of 12,858 person-year-observations (PYO) resulting in a mortality rate of 12.4 deaths/100 PYO (95% confidence interval [CI], 11.3-13.0). An initial decline in mortality rates was observed prior to 1999, probably because of an increase in the proportion of less symptomatic patients. After the introduction of the national highly active antiretroviral therapy (HAART) program, a profound decline in mortality rates was observed, reaching 2.0 deaths/100 PYO (95% CI, 1.4-2.9) in 2010. Simultaneously, the number of patients on follow-up increased by nearly fourfold. Although HAART has drastically improved the survival of HIV-infected patients, the number of patients receiving therapy at this HIV clinic has substantially increased. While referral of HIV patients to general physicians' care should be urged, we cannot overemphasize the importance of preventing new HIV infections.

Impact of the National Access to Antiretroviral Program on the incidence of opportunistic infections in Thailand.

The National Access to Antiretroviral Program caused a decline in HIV mortality in Thailand, but its impact on opportunistic infections (OI) remains unknown. The aim of this study was to compare the incidence of different OIs before and after the initiation of highly active antiretroviral therapy (HAART). Data from a prospective cohort at a hospital in northern Thailand were analysed. In total, 704 patients enrolled from July 2000 to October 2002 and not on HAART were followed up until October 2004. In addition, 409 patients who started HAART between April 2002 and January 2004 were followed up for 24 months. The impact of HAART on OIs was analysed using Cox proportional hazard models. HAART was associated with a strong reduction in OIs. The reduction appeared to vary by type: tuberculosis (TB), adjusted hazard ratio (AHR) = 0.2 (95% CI 0.1-0.5); pneumocystis pneumonia (PCP), AHR = 0.03 (95% CI 0.007-0.1); cryptococcal meningitis, AHR = 0.2 (95% CI 0.1-0.5); and penicilliosis, AHR = 0.1 (95% CI 0.06-0.3). In conclusion, HAART was very effective in reducing OIs, especially PCP. TB and cryptococcal meningitis remained frequent in the early phase of antiretroviral drug therapy. More attention to prophylaxis as well as earlier diagnosis and starting treatment for these OIs is recommended.

Appearance of Drug Resistance-Associated Mutations in Human Immunodeficiency Virus Type 1 CRF01_AE Integrase Derived from Drug-Naive Thai Patients.

CRF01_AE is a major subtype of human immunodeficiency virus type 1 (HIV-1) circulating in Southeast Asia, including Thailand. We performed genotypic studies on HIV-1 CRF01_AE integrase derived from plasma samples from drug-naive Thai patients. Direct sequencing of amplified CRF01_AE integrase genes revealed that although no primary mutations associated with drug resistance to integrase inhibitors were detected, at least one secondary mutation was found in 96% of samples. Our results indicate that the impact of these mutations on the baseline drug susceptibility of CRF01_AE viruses to integrase inhibitors may need to be addressed prior to the introduction of these drugs in Southeast Asian countries, including Thailand.

HLA-associated immune pressure on Gag protein in CRF01_AE-infected individuals and its association with plasma viral load.

BACKGROUND: The human leukocyte antigen (HLA)-restricted cytotoxic T-lymphocyte (CTL) immune response is one of the major factors determining the genetic diversity of human immunodeficiency virus (HIV). There are few population-based analyses of the amino acid variations associated with the host HLA type and their clinical relevance for the Asian population. Here, we identified HLA-associated polymorphisms in the HIV-1 CRF01_AE Gag protein in infected married couples, and examined the consequences of these HLA-selected mutations after transmission to HLA-unmatched recipients. METHODOLOGY/PRINCIPAL FINDINGS: One hundred sixteen HIV-1-infected couples were recruited at a government hospital in northern Thailand. The 1.7-kb gag gene was amplified and directly sequenced. We identified 56 associations between amino acid variations in Gag and HLA alleles. Of those amino acid variations, 35 (62.5%) were located within or adjacent to regions reported to be HIV-specific CTL epitopes restricted by the relevant HLA. Interestingly, a significant number of HLA-associated amino acid variations appear to be unique to the CRF01_AE-infected Thai population. Variations in the capsid protein (p24) had the strongest associations with the viral load and CD4 cell count. The mutation and reversion rates after transmission to a host with a different HLA environment varied considerably. The p24 T242N variant escape from B57/58 CTL had a significant impact on the HIV-1 viral load of CRF01_AE-infected patients. CONCLUSIONS/SIGNIFICANCE: HLA-associated amino acid mutations and the CTL selection pressures on the p24 antigen appear to have the most significant impact on HIV replication in a CRF01_AE-infected Asian population. HLA-associated mutations with a low reversion rate accumulated as a footprint in this Thai population. The novel HLA-associated mutations identified in this study encourage us to acquire more extensive information about the viral dynamics of HLA-associated amino acid polymorphisms in a given population as effective CTL vaccine targets.

The role of lysine residue at amino acid position 165 of human immunodeficiency virus type 1 CRF01_AE Gag in reducing viral drug susceptibility to protease inhibitors.

Recombinant human immunodeficiency virus type 1 (HIV-1) containing a CRF01_AE Gag, AE-Gag62, was significantly less susceptible to protease inhibitors (PIs) than the subtype B reference strain, NL4-3; therefore, the mechanism of how AE-Gag62 reduced viral drug susceptibility to PIs was studied in this report. The results showed that the lysine residue at amino acid position 165 (K165) of AE-Gag62 played a role in reducing the drug susceptibility of the recombinant virus to PIs. In addition, K165 potentially appears more frequently in CRF01_AE viruses than in the viruses of other major HIV-1 subtypes. Although K165 had no effect on the extent of recombinant protease-mediated in vitro Gag cleavage, it enhanced the incorporation of the Gag-Pol precursor protein, p160, into virions. Taken together, these results suggest that K165 of CRF01_AE Gag affects the regulation of virion assembly or maturation, and reduces viral drug susceptibility to PIs.

Design and evaluation of antiretroviral peptides corresponding to the C-terminal heptad repeat region (C-HR) of human immunodeficiency virus type 1 envelope glycoprotein gp41.

Two alpha-helical heptad repeats, N-HR and C-HR, located in the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp41, play an important role in membrane fusion by forming a 6-helix bundle. C34, a peptide mimicking C-HR, inhibits the formation of the 6-helix bundle; thus, it has potential as a novel antiretroviral compound. In order to improve the inhibitory effect of C34 on HIV-1 replication, we designed new C34-derived peptides based on computational analysis of the stable conformation of the 6-helix bundle. Newly designed peptides showed a stronger inhibitory effect on the replication of recombinant viruses containing CRF01_AE, subtype B or subtype C Env than C34 or a fusion inhibitor, T-20. In addition, these peptides inhibited the replication of a T-20-resistant virus. We propose that these peptides could be applied to develop novel antiretroviral compounds to inhibit the replication of various subtypes of HIV-1 as well as of T-20-resistant variants.

Drug-resistant mutation patterns in CRF01_AE cases that failed d4T+3TC+nevirapine fixed-dosed, combination treatment: Follow-up study from the Lampang cohort.

HIV/AIDS patients are treated in Thailand's national antiretroviral treatment (ART) program with a generic combination tablet of stavudine, lamivudine, and nevirapine (GPOvir). To determine GPOvir-resistant mutations, HIV-1 sequences of 59 GPOvir-failure cases from the Lampang cohort were compared with sequences from 76 randomly selected ART-naïve cases. The GPOvir-failure cases had not only known stavudine-, lamivudine- and nevirapine-resistant mutations, but also V118I, G196E, and H221Y. Among the 59 GPOvir-failure cases, 29 were ART-naïve prior to GPOvir (naïve group), and 30 had previous ART (exposed group). To clarify the effect of previous ART in drug-resistant acquisition pathways, naïve and exposed groups were compared. The exposed group had predominantly thymidine analogue-related mutations, whereas the naïve group had a higher prevalence of Q151M and K103N mutations. M184V lamivudine resistance was most frequent in both naïve and exposed groups. To identify which mutations in CRF01_AE pol were polymorphisms, the connection and RNase domains were also analyzed. CRF01_AE-specific polymorphisms were found in 19 residues, and GPOvir-failure cases had significantly higher frequency of N348I, E399D, P537S, and I542M. Our results expand identification of mutations in CRF01_AE pol that are polymorphisms by also analyzing the connection and RNase H domains.

Two N-linked glycosylation sites in the V2 and C2 regions of human immunodeficiency virus type 1 CRF01_AE envelope glycoprotein gp120 regulate viral neutralization susceptibility to the human monoclonal antibody specific for the CD4 binding domain.

A recombinant human monoclonal antibody, IgG1 b12 (b12), recognizes a conformational epitope on human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) gp120 that overlaps the CD4 binding domain. Although b12 is able to broadly neutralize HIV-1 subtype B, C, and D viruses, many HIV-1 CRF01_AE viruses are resistant to b12-mediated neutralization. In this report, we examined the molecular mechanisms underlying the low neutralization susceptibility of CRF01_AE viruses to b12, using recently established CRF01_AE Env recombinant viruses. Our results showed that two potential N-linked glycosylation (PNLG) sites in the V2 and C2 regions of Env gp120 played an important role in regulating the susceptibility of CRF01_AE Env to b12. The locations of these PNLG sites correspond to amino acid positions 186 and 197 in HXB2 Env gp120; thus, they are designated N186 and N197 in this study. Removal of N186 significantly conferred the b12 susceptibility of 2 resistant CRF01_AE Env clones, 65CC4 and 107CC2, while the introduction of N186 reduced the b12 susceptibility of a susceptible CRF01_AE Env clone, 65CC1. In addition, removal of both N186 and N197 conferred the b12 susceptibility of 3 resistant CRF01_AE Env clones, 45PB1, 62PL1, and 101PL1, whereas the removal of either N186 or N197 was not sufficient to confer the b12 susceptibility of these CRF01_AE Env clones. Finally, removal of N197 conferred the b12 susceptibility of 2 resistant CRF01_AE Env clones lacking N186, 55PL1 and 102CC2. Taken together, we propose that two PNLG sites, N186 and N197, in Env gp120 are important determinants of the b12 resistance of CRF01_AE viruses.

Amantadine- and oseltamivir-resistant variants of influenza A viruses in Thailand.

Amantadine and oseltamivir are used to treat influenza A virus infections; however, resistance to these drugs has been widely reported throughout the world. In this study, the frequency and genetic characteristics of the drug-resistant influenza A viruses that circulated in Thailand from 2006 to 2008 were investigated. The nucleotide sequences of the NA and M2 genes were elucidated in order to identify mutations that confer oseltamivir- and amantadine-resistant phenotypes, respectively. A total of 66 influenza A viruses including 44 H1N1 and 22 H3N2 subtypes isolated in Bangkok and 13 provinces of Thailand from 2006 to 2008 were analyzed. Our results demonstrated that seven out of 32 (22%) of the H1N1 viruses isolated in 2006 in Thailand carried the amino acid S31N substitution, which confers amantadine-resistance, although no isolates in 2007 or 2008 possessed the mutation. In the cases of oseltamivir-resistance, four of 10 (40%) of the H1N1 viruses isolated in 2008 were predicted to be resistant to the drug, although none of the 34 viruses isolated in 2006 or 2007 were predicted to be resistant. Surprisingly, all 9 H3N2 viruses isolated in 2008 appeared to be resistant to the amantadine and none were resistant in 2006 or 2007. Phylogenetic analysis based on the HA, M, and NA genes demonstrated that the amantadine-resistant H1N1 isolates had been produced by genetic reassortment. All of the amantadine-resistant H3N2 viruses were clustered in one of these three genes and possessed double mutations of S193F and D225N in the HA gene.

Impact of amino acid variations in Gag and protease of HIV type 1 CRF01_AE strains on drug susceptibility of virus to protease inhibitors.

BACKGROUND: Protease (PR) inhibitors (PIs) were designed against subtype B virus of human immunodeficiency virus type 1 (HIV-1), but believed to retain its activity against most of the other subtypes. CRF01_AE PR (AE-PR) contains background mutations that are presumed to alter the drug susceptibility of PR. In addition, amino acid variations found in HIV-1 Gag potentially affect the drug susceptibility or catalytic efficiency of PR. METHODS: We studied the impact of naturally occurring amino acid substitutions found in AE-PR and CRF01_AE Gag (AE-Gag) on the drug susceptibility of PR to 9 currently available PIs, using the pNL4-3-derived luciferase reporter virus containing AE-Gag and/or AE-PR genes derived from drug treatment-naïve, HIV-1-infected Thai patients. RESULTS: Sequencing analysis revealed that several mutations were detected in deduced amino acid sequences of AE-PR and AE-Gag genes, as compared to these genes of pNL4-3. Drug susceptibility tests revealed that AE-PR showed a variety of susceptibilities to 9 PIs compared with pNL4-3 PR. In addition, AE-Gag significantly reduced the drug susceptibility of AE-PR and pNL4-3 PR. CONCLUSION: Our results suggest that amino acid variations in AE-PR and AE-Gag play roles in determining the drug susceptibility of CRF01_AE viruses to PIs.

Short communication: RNA interference directed against Axin1 upregulates human immunodeficiency virus type 1 gene expression by activating the Wnt signaling pathway in HeLa-derived J111 cells.

Axin1, a regulator of Wnt signaling, was previously identified as playing a negative role in the late phase of human immunodeficiency virus type 1 (HIV-1) replication in HeLa-derived J111 cells. In this report, we studied the molecular mechanism of how Axin1 regulates HIV-1 replication. HIV-1 transactivator, Tat-dependent viral reporter gene expression was enhanced in J111 cells transfected with small interfering RNA (siRNA) against Axin1. In addition, viral transcription was upregulated in J111 cells transfected with siRNA against Axin1. In contrast, HIV-1 gene expression was not enhanced by transfecting HeLa cells with siRNA against Axin1. The expression levels of T cell factor-4 (TCF4) and beta-catenin were higher in J111 than HeLa cells. In addition, siRNAs against TCF4 and beta-catenin inhibited the Axin1 siRNA-dependent enhancement of HIV-1 gene expression in J111 cells. These results suggest that Axin1 plays a negative role in HIV-1 transcription through the Wnt signaling pathway in J111 cells under normal cell culture conditions.

Detection of drug resistance-associated and background mutations in human immunodeficiency virus type 1 CRF01_AE protease and reverse transcriptase derived from drug treatment-naive patients residing in central Thailand.

CRF01_AE is a major subtype of human immunodeficiency virus type 1 (HIV-1) circulating in Southeast Asia, including Thailand. We performed genotypic studies on HIV-1 CRF01_AE protease (PR) and reverse transcriptase (RT) derived from plasma samples from drug treatment-naive patients residing in central Thailand. Direct sequencing of amplified CRF01_AE PR and RT genes revealed that drug resistance-associated as well as background mutations were frequently detected in CRF01_AE PR. In contrast, although several background mutations were detected, no drug resistance-associated mutations were observed in CRF01_AE RT. Antiretroviral drugs, including PR inhibitors, have been increasingly used in Thailand. To achieve effective antiretroviral therapy, we propose that it is important to reveal the prevalence of drug resistance-associated mutations among drug treatment-naive patients by further surveillance studies.

Demographic, socio-economic, behavioral and clinical factors predicting virologic failure with generic fixed-dose combination antiretroviral therapy before universal health insurance coverage in northern Thailand.

We conducted a 2-year prospective cohort study to investigate multiple aspects of factors predicting the outcome of fixed-dose combination antiretroviral (ARV) therapy with lamivudine, stavudine, and nevirapine (GPOvir) at a government referral hospital in northern Thailand. At 6 and 24 months after the initiation of GPOvir, viral load (VL) was measured to determine virologic failure (>400 RNA copies/ml) and demographic, socio-economic, behavioral and clinical data were collected. From 10 April 2002 to 31 January 2004, 409 patients participated in this study: 64/364 (17.0%) at 6 months and 55/345 (15%) at 24 months virologically failed treatment. On univariate analysis, besides ARV experience [odds ratio (OR), 3.08, 95% confidence interval (CI), 1.71 -5.57] and the frequency of delayed doses (OR, 2.97; 95% CI, 1.47-6.00), we identified one socioeconomic factor significantly associated with virologic failure: "not having child" (OR, 1.85; 95% CI, 1.03 - 3.34). Although the association with "not having child" became marginal on multivariate analysis, results of in-depth interviews and group discussions indicated that having a child was a strong motivating factor for good treatment compliance. We suggest that patients without children may need more attention. Further investigation of socio-economic factors is warranted.

Substantially exposed but HIV-negative individuals are accumulated in HIV-serology-discordant couples diagnosed in a referral hospital in Thailand.

The objectives of this study is to characterize HIV-serology-discordant couples diagnosed at a referral hospital in Thailand and to identify risk factors for HIV transmission among married couples. Firstly, cross-sectional analysis was conducted from July 2000 to October 2002. Out of 216 HIV-positive married men who knew the HIV status of their wives, the median number of sexual contacts in 63 men with HIV-negative wives was 6 times per month before the disclosure of HIV status, which did not differ from 153 men with HIV-positive wives. The majority of men with HIV-negative wives never used condoms. The median duration of marriage was 7 years for both groups. Unlike in previous reports, men with HIV-negative wives were significantly more symptomatic (P<0.01), and their CD4+ counts and viral loads did not differ from men with HIV-positive wives. Secondarily, 71 initially discordant couples were longitudinally followed until March 2005. Four were seroconverted out of 132.24 person-years of observation. In multivariate analysis incorporating sex, age, CD4+ count and sexual contact without a condom, shorter duration of marriage (<2 years) was found to be the only risk factor significantly associated with HIV transmission (hazard ratio of 15.2, P=0.04). Individuals substantially exposed to HIV but remaining HIV-negative are accumulated in discordant couples identified in a hospital, except in recently married couples.

Phenotypic studies on recombinant human immunodeficiency virus type 1 (HIV-1) containing CRF01_AE env gene derived from HIV-1-infected patient, residing in central Thailand.

Human immunodeficiency virus type 1 (HIV-1) env genes were cloned from blood samples of HIV-1-infected Thai patients, and 35 infectious CRF01_AE envelope glycoprotein (Env)-recombinant viruses were established. In this report, we examined the neutralization susceptibility of these viruses to human monoclonal antibodies, 2G12, IgG1 b12, 2F5 and 4E10, pooled patient plasma, coreceptor antagonists and fusion inhibitor, T-20. The neutralization susceptibility of CRF01_AE Env-recombinant viruses to 2F5, 4E10, patient plasma, coreceptor antagonists and T-20 varied, while most viruses showed low susceptibility to 2G12 and IgG1 b12. Several dual-tropic viruses showed lower susceptibility to 2F5 and 4E10 than CXCR4- or CCR5-tropic viruses. Neutralization susceptibility of the CRF01_AE Env-recombinant virus to pooled patient plasma was negatively correlated with the length of the V1/V2 region or the number of potential N-linked glycosylation sites in conserved regions of gp120. No correlation was found between the coreceptor usage and neutralization susceptibility of the virus to T-20, whereas several dual-tropic viruses showed higher susceptibility to coreceptor antagonists than CXCR4- or CCR5-tropic viruses. We propose that these CRF01_AE Env-recombinant viruses are useful to further study the molecular mechanism of the susceptibility of CRF01_AE Env to neutralizing antibodies and viral entry inhibitors.

Genotypic characterization of CRF01_AE env genes derived from human immunodeficiency virus type 1-infected patients residing in central Thailand.

CRF01_AE is a major subtype of human immunodeficiency virus type 1 (HIV-1) circulating in Southeast Asia, including Thailand. HIV-1 env genes were amplified by polymerase chain reaction from blood samples of HIV-1-infected patients residing in Thailand in 2006, and cloned into the pNL4-3-derived reporter viral construct. Generated envelope protein (Env)-recombinant virus was examined for its infectivity, and then 35 infectious CRF01_AE Env-recombinant viruses were selected. Sequencing analysis revealed that the interclone variation of the deduced amino acid sequences was higher in CRF01_AE env genes isolated in 2006 than in those isolated in the early 1990s, suggesting that env gene variation has been increasing gradually among CRF01_AE viruses prevalent in Thailand. We also examined the characteristics of the deduced amino acid sequences of 35 CRF01_AE env genes. Our results may provide useful information to help in better understanding the genotype of env genes of CRF01_AE viruses currently circulating in Thailand.

Higher in vitro susceptibility of human T cells to H5N1 than H1N1 influenza viruses.

Patients infected with H5N1 influenza A virus, who had a severe or fatal outcome, exhibited several characteristic clinical manifestations including lymphopenia. In this study, human CD4(+) T-cell lines and healthy donor-derived peripheral blood mononuclear cells (PBMCs) were examined for susceptibility to infection with Thai isolates of H5N1 in comparison to those of H1N1. Although cellular levels were variable between H5N1 and H1N1 in T-cell lines and PBMCs, rates of production of progeny virions were significantly higher in H5N1 infections, suggesting a more efficient release of virions. In addition, cytopathogenicity in PBMCs, leading to a decline in CD4(+) T-cell numbers, were much severer with H5N1 than H1N1. Thus, human T cells could be an important target for infection with H5N1.

A nationally coordinated laboratory system for human avian influenza A (H5N1) in Thailand: program design, analysis, and evaluation.

BACKGROUND: The first phase of national surveillance for avian influenza (H5N1) human disease in Thailand occurred over a 4-month period that began on 1 December 2003. Subsequently, a nationally coordinated laboratory system (NCLS) for avian influenza (H5N1) was created to assess population-based surveillance, specimen procurement, case detection, and reporting at the national level. METHODS: We conducted a pre- and postintervention study to evaluate the NCLS designed during the 6-week interval from 1 April through 15 May 2004. During the pre-NCLS period (1 December 2003 through 31 March 2004), 12 cases of human avian influenza (H5N1) were confirmed. During the post-NCLS period (16 May 2004 through 31 December 2006), interventions were implemented for human avian influenza (H5N1) surveillance, case detection, and expedited, computer-based reporting. RESULTS: During the pre- and post-NCLS periods, 777 (85%) of 915 and 10,434 (95%) of 11,042 clinical respiratory specimens, respectively, were adequate for confirmatory testing (P<.001), the median time from procurement to results decreased from 17 days (range, 14-24 days) to 1.8 days (range, 0.25-4 days; P<.001), and the duration of specimen shipment decreased from 46.5 h to 21.1 h (P<.001). Thirteen cases of avian influenza (H5N1) were detected during the 31-month postintervention period. H5N1 reverse-transcriptase polymerase chain reaction and real-time reverse-transcriptase polymerase chain reaction sensitivity was 100% and specificity was 99.8%. CONCLUSIONS: The NCLS exemplifies a systematic approach to national surveillance for avian influenza A (H5N1). This NCLS program in Thailand serves as a model for human avian influenza (H5N1) preparedness that can be adopted or modified for use in other countries.

Effects of CCR2 and CCRS polymorphisms on HIV-1 infection in Thai females.

Polymorphisms in CCR2 and CCR5 genes reportedly affect HIV-1 transmission and disease progression in HIV-1-infected individuals. In the study presented here, we examined the effects of CCR2 and CCR5 polymorphisms on HIV-1 transmission in 74 Thai females who were exposed to HIV but seronegative (ESN) and in 347 HIV-seropositive females. We found that the combination of 2 non-synonymous substitutions, CCR2 V64I and CCR5 G316A, tended to occur more frequently in ESN females (2 of 74) than in HIV-1 infected females (1 of 347) (P = 0.08). This suggested that non-synonymous substitution in the CCR5 gene also affects HIV-1 transmission in an Asian population in which the CCR5-Delta32 is very rare.