Displaying publications 61 - 80 of 137 in total

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  1. Yee PTI, Mohamed RAH, Ong SK, Tan KO, Poh CL
    Virus Res, 2017 06 15;238:243-252.
    PMID: 28705680 DOI: 10.1016/j.virusres.2017.07.010
    One of the leading causes of the hand, foot and mouth disease (HFMD) is Enterovirus 71 (EV-A71), displaying symptoms such as fever and ulcers in children but some strains can produce cardiopulmonary oedema which leads to death. There is no FDA-approved vaccine for prevention of severe HFMD. The molecular determinants of virulence for EV-A71 are unclear. It could be a single or a combination of amino acids that determines virulence in different EV-A71 genotype/sub-genotypes. Several EV-A71 strains bearing single nucleotide (nt) mutations were constructed and the contribution of each mutation to virulence was evaluated. The nt(s) that contributed to significant reduction in virulence in vitro were selected and each mutation was introduced separately into the genome to construct the multiply mutated EV-A71 strain (MMS) which carried six substitutions of nt(s) at the 5'-NTR (U700C), VP1-145 (E to G), VP1-98E, VP1-244K and G64R in the vaccine seed strain that had a partial deletion within the 5'-NTR region (nt. 475-485) of Δ11bp. In comparison to the wild type strain, the MMS showed low virulence as it produced very low RNA copy number, plaque count, VP1 and had 105-fold higher TCID50, indicative of a promising LAV candidate that should be further evaluated in vivo.
    Matched MeSH terms: Viral Load
  2. Kosalaraksa P, Boettiger DC, Bunupuradah T, Hansudewechakul R, Saramony S, Do VC, et al.
    J Pediatric Infect Dis Soc, 2017 Jun 01;6(2):173-177.
    PMID: 27295973 DOI: 10.1093/jpids/piw031
    Background.: Regular CD4 count testing is often used to monitor antiretroviral therapy efficacy. However, this practice may be redundant in children with a suppressed human immunodeficiency virus (HIV) viral load.

    Methods: Study end points were as follows: (1) a CD4 count <200 cells/mm3 followed by a CD4 count ≥200 cells/mm3 (transient CD4 <200); (2) CD4 count <200 cells/mm3 confirmed within 6 months (confirmed CD4 <200); and (3) a new or recurrent World Health Organization (WHO) stage 3 or 4 illness (clinical failure). Kaplan-Meier curves and Cox regression were used to evaluate rates and predictors of transient CD4 <200, confirmed CD4 <200, and clinical failure among virally suppressed children aged 5-15 years who were enrolled in the TREAT Asia Pediatric HIV Observational Database.

    Results: Data from 967 children were included in the analysis. At the time of confirmed viral suppression, median age was 10.2 years, 50.4% of children were female, and 95.4% were perinatally infected with HIV. Median CD4 cell count was 837 cells/mm3, and 54.8% of children were classified as having WHO stage 3 or 4 disease. In total, 18 transient CD4 <200 events, 2 confirmed CD4 <200 events, and10 clinical failures occurred at rates of 0.73 (95% confidence interval [95% CI], 0.46-1.16), 0.08 (95% CI, 0.02-0.32), and 0.40 (95% CI, 0.22-0.75) events per 100 patient-years, respectively. CD4 <500 cells/mm3 at the time of viral suppression confirmation was associated with higher rates of both CD4 outcomes.

    Conclusions: Regular CD4 testing may be unnecessary for virally suppressed children aged 5-15 years with CD4 ≥500 cells/mm3.

    Matched MeSH terms: Viral Load
  3. Kristeen-Teo YW, Yeap SK, Tan SW, Omar AR, Ideris A, Tan SG, et al.
    BMC Vet Res, 2017 May 31;13(1):151.
    PMID: 28569155 DOI: 10.1186/s12917-017-1071-y
    BACKGROUND: Virulent Newcastle disease virus (NDV) was reported to cause rapid depletion of chicken bursa of Fabricius. Severe pathological condition of the organ is commonly associated with high levels of virus replication, intense inflammatory response and also the degree of apoptosis. In this study, the responses of chicken bursa of Fabricius infected with two different strains of velogenic NDV, namely AF2240 and IBS002, were investigated by observing cell population changes, oxidative stress, viral replication and cytokine expression in the organ. Subsequently, apoptosis of enriched bursal IgM+ cells was determined to help us elucidate possible host pathogen relationships between the chicken bursa of Fabricius and NDV infection.

    RESULTS: The depletion of IgM+ cells and infiltration of macrophages were observed to be higher in bursa infected with AF2240 as compared to IBS002. In line with the increment of the macrophage population, higher nitric oxide (NO) and malondialdehyde (MDA) contents which indicated higher oxidative stress were also detected in bursa infected with NDV AF2240. In addition, higher pro-inflammatory cytokines and chemokine gene expression such as chicken CXCLi2, IL-18 and IFN-γ were observed in AF2240 infected bursa. Depletion of IgM+ cells was further confirmed with increased cell death and apoptosis of the cells in AF2240 infected bursa as compared to IBS002. However, it was found that the viral load for NDV strain IBS002 was comparatively higher than AF2240 although the magnitude of the pro- inflammatory cytokines expression and cell apoptosis was lower than AF2240.

    CONCLUSION: The results of our study demonstrated that infection of NDV strains AF2240 and IBS002 caused apoptosis in bursa IgM+ cells and its severity was associated with increased expression of pro-inflammatory cytokines/chemokine, macrophage infiltration and oxidative stress as the infection duration was prolonged. However, of the two viruses, we observed that NDV AF2240 induced a greater magnitude of apoptosis in chicken bursa IgM+ cells in comparison to IBS002. This might be due to the high level of oxidative stress and inflammatory cytokines/chemokine as well as lower IL10 expression which subsequently led to a high rate of apoptosis in the chicken bursa of Fabricius although the detected viral load of AF2240 was lower than IBS002.

    Matched MeSH terms: Viral Load
  4. Jamal Mohamed T, Teeraananchai S, Kerr S, Phongsamart W, Nik Yusoff NK, Hansudewechakul R, et al.
    AIDS Res Hum Retroviruses, 2017 03;33(3):230-233.
    PMID: 27758114 DOI: 10.1089/AID.2016.0039
    We sought to assess the impact of routine HIV viral load (VL) monitoring on the incidence of switching from a first- to a second-line antiretroviral therapy (ART) regimen, and to describe factors associated with switch. Data from a regional cohort of 16 clinical programs in six Asian countries were analyzed. Second-line switch was defined as a change from a non-nucleoside reverse transcriptase inhibitor (NNRTI) to a protease inhibitor (PI) or vice versa, and ≥1 of the following: (1) reported treatment failure by local criteria, (2) switch of ≥1 additional drug, or (3) a preceding HIV VL ≥1,000 copies/ml. Routine VL was having ≥1 test after ≥24 weeks of ART and ≥1 time/year thereafter. Factors associated with time to switch were evaluated with death and loss to follow-up as competing risks. A total of 2,398 children were included in this analysis. At ART initiation, the median (interquartile range) age was 6.0 (3.3-8.9) years, more than half had WHO stage 3 or 4, the median CD4 was 189 (47-456) cells/mm3, 93% were on NNRTI-based first-line ART, and 34% had routine VL monitoring. Treatment switch occurred in 17.6% of patients, at a median of 35 (22-49) months. After adjusting for country, sex, first ART regimen, and CD4% at ART initiation, children with routine VL monitoring were 1.46 (95% confidence interval 1.11-1.93) times more likely to be switched (p = .007). Scale-up of VL testing will lead to earlier identification of treatment failure, and it can help guide earlier switches to prevent resistance.
    Matched MeSH terms: Viral Load*
  5. Durier N, Yunihastuti E, Ruxrungtham K, Kinh NV, Kamarulzaman A, Boettiger D, et al.
    J Viral Hepat, 2017 03;24(3):187-196.
    PMID: 27917597 DOI: 10.1111/jvh.12630
    Data on markers of hepatitis C virus (HCV) disease in HIV-HCV-coinfected patients in resource-limited settings are scarce. We assessed HCV RNA, HCV genotype (GT), IL28B GT and liver fibrosis (FibroScan® ) in 480 HIV-infected patients with positive HCV antibody in four HIV treatment centres in South-East Asia. We enrolled 165 (34.4%) patients in Jakarta, 158 (32.9%) in Bangkok, 110 (22.9%) in Hanoi and 47 (9.8%) in Kuala Lumpur. Overall, 426 (88.8%) were male, the median (IQR) age was 38.1 (34.7-42.5) years, 365 (76.0%) reported HCV exposure through injecting drug use, and 453 (94.4%) were on combination antiretroviral therapy. The median (IQR) CD4 count was 446 (325-614) cells/mm3 and 208 (94.1%) of 221 patients tested had HIV-1 RNA <400 copies/mL. A total of 412 (85.8%) had detectable HCV RNA, at a median (IQR) of 6.2 (5.4-6.6) log10 IU/mL. Among 380 patients with HCV GT, 223 (58.7%) had GT1, 97 (25.5%) had GT3, 43 (11.3%) had GT6, eight (2.1%) had GT4, two (0.5%) had GT2, and seven (1.8%) had indeterminate GT. Of 222 patients with IL28B testing, 189 (85.1%) had rs12979860 CC genotype, and 199 (89.6%) had rs8099917 TT genotype. Of 380 patients with FibroScan® , 143 (37.6%) had no/mild liver fibrosis (F0-F1), 83 (21.8%) had moderate fibrosis (F2), 74 (19.5%) had severe fibrosis (F3), and 79 (20.8%) had cirrhosis (F4). One patient (0.3%) had FibroScan® failure. In conclusion, a high proportion of HIV-HCV-coinfected patients had chronic HCV infection. HCV GT1 was predominant, and 62% of patients had liver disease warranting prompt treatment (≥F2).
    Matched MeSH terms: Viral Load
  6. Barathan M, Mohamed R, Vadivelu J, Chang LY, Vignesh R, Krishnan J, et al.
    Cell Immunol, 2017 03;313:1-9.
    PMID: 28104239 DOI: 10.1016/j.cellimm.2016.12.002
    Hepatitis C virus (HCV)-specific CD4+ and CD8+ T cells are key to successful viral clearance in HCV disease. Accumulation of exhausted HCV-specific T cells during chronic infection results in considerable loss of protective functional immune responses. The role of T-cell exhaustion in chronic HCV disease remains poorly understood. Here, we studied the frequency of HCV peptide-stimulated T cells expressing negative immune checkpoints (PD-1, CTLA-4, TRAIL, TIM-3 and BTLA) by flow cytometry, and measured the levels of Th1/Th2/Th17 cytokines secreted by T cells by a commercial Multi-Analyte ELISArray™ following in vitro stimulation of T cells using HCV peptides and phytohemagglutinin (PHA). HCV peptide-stimulated CD4+ and CD8+ T cells of chronic HCV (CHC) patients showed significant increase of CTLA-4. Furthermore, HCV peptide-stimulated CD4+ T cells of CHC patients also displayed relatively higher levels of PD-1 and TRAIL, whereas TIM-3 was up-regulated on HCV peptide-stimulated CD8+ T cells. Whereas the levels of IL-10 and TGF-β1 were significantly increased, the levels of pro-inflammatory cytokines IL-2, TNF-α, IL-17A and IL-6 were markedly decreased in the T cell cultures of CHC patients. Chronic HCV infection results in functional exhaustion of CD4+ and CD8+ T cells likely contributing to viral persistence.
    Matched MeSH terms: Viral Load
  7. Lei W, Guo X, Fu S, Feng Y, Tao X, Gao X, et al.
    Vet Microbiol, 2017 Mar;201:32-41.
    PMID: 28284620 DOI: 10.1016/j.vetmic.2017.01.003
    BACKGROUND: Since the turn of the 21st century, there have been several epidemic outbreaks of poultry diseases caused by Tembusu virus (TMUV). Although multiple mosquito and poultry-derived strains of TMUV have been isolated, no data exist about their comparative study, origin, evolution, and dissemination.

    METHODOLOGY: Parallel virology was used to investigate the phenotypes of duck and mosquito-derived isolates of TMUV. Molecular biology and bioinformatics methods were employed to investigate the genetic characteristics and evolution of TMUV.

    PRINCIPAL FINDINGS: The plaque diameter of duck-derived isolates of TMUV was larger than that of mosquito-derived isolates. The cytopathic effect (CPE) in mammalian cells occurred more rapidly induced by duck-derived isolates than by mosquito-derived isolates. Furthermore, duck-derived isolates required less time to reach maximum titer, and exhibited higher viral titer. These findings suggested that poultry-derived TMUV isolates were more invasive and had greater expansion capability than the mosquito-derived isolates in mammalian cells. Variations in amino acid loci in TMUV E gene sequence revealed two mutated amino acid loci in strains isolated from Malaysia, Thailand, and Chinese mainland compared with the prototypical strain of the virus (MM1775). Furthermore, TMUV isolates from the Chinese mainland had six common variations in the E gene loci that differed from the Southeast Asian strains. Phylogenetic analysis indicated that TMUV did not exhibit a species barrier in avian species and consisted of two lineages: the Southeast Asian and the Chinese mainland lineages. Molecular traceability studies revealed that the recent common evolutionary ancestor of TMUV might have appeared before 1934 and that Malaysia, Thailand and Shandong Province of China represent the three main sources related to TMUV spread.

    CONCLUSIONS: The current broad distribution of TMUV strains in Southeast Asia and Chinese mainland exhibited longer-range diffusion and larger-scale propagation. Therefore, in addition to China, other Asian and European countries linked to Asia have used improved measures to detect and monitor TMUV related diseases to prevent epidemics in poultry.

    Matched MeSH terms: Viral Load
  8. Abba Y, Hassim H, Hamzah H, Ibrahim OE, Mohd Lila MA, Noordin MM
    Microb Pathog, 2017 Mar;104:17-27.
    PMID: 28062291 DOI: 10.1016/j.micpath.2017.01.003
    Boid inclusion body disease (BIBD) is a viral disease of boid snakes believed to be caused by reptarenavirus belonging to the family Arenaviridae. Unlike most mammalian arenaviruses, the reservoir host for reptarenavirus is still unknown. In this study, the pathological responses were evaluated in a mouse model for a period of 28 days. Blood and tissue samples (lung, liver, spleen, heart, kidney and brain) were collected for evaluation of hematology, biochemistry, histopathology and oxidative enzyme levels at six time points (1, 3, 7, 14, 21 and 28 days), after viral infection (2.0 × 10(6) pfu/mL) in the infected and normal saline in the control groups. An initial increase (p Viral counts were low on days 7 and 14 but surged in both the liver and spleen on day 21 and 28. This study has shown that reptarenavirus replicates in mammalian host and induces oxidative stress. Furthermore, the resultant hematobiochemical and histopathological changes observed in infected mice were similar to what has been reported in mammarenavirus infections. This suggests that rodents may serve as potential reservoir hosts for reptarenavirus.
    Matched MeSH terms: Viral Load
  9. Boyd MA, Amin J, Mallon PW, Kumarasamy N, Lombaard J, Wood R, et al.
    Lancet HIV, 2017 01;4(1):e13-e20.
    PMID: 27815068 DOI: 10.1016/S2352-3018(16)30189-8
    BACKGROUND: Lipoatrophy is one of the most feared complications associated with the use of nucleoside or nucleotide reverse transcriptase inhibitors (N[t]RTIs). We aimed to assess soft-tissue changes in participants with HIV who had virological failure of a first-line antiretroviral (ART) regimen containing a non-nucleoside reverse transcriptase inhibitor plus two N(t)RTIs and were randomly assigned to receive a second-line regimen containing a boosted protease inhibitor given with either N(t)RTIs or raltegravir.

    METHODS: Of the 37 sites that participated in the randomised, open-label, non-inferiority SECOND-LINE study, eight sites from five countries (Argentina, India, Malaysia, South Africa, and Thailand) participated in the body composition substudy. All sites had a dual energy x-ray absorptiometry (DXA) scanner and all participants enrolled in SECOND-LINE were eligible for inclusion in the substudy. Participants were randomly assigned (1:1), via a computer-generated allocation schedule, to receive either ritonavir-boosted lopinavir plus raltegravir (raltegravir group) or ritonavir-boosted lopinavir plus two or three N(t)RTIs (N[t]RTI group). Randomisation was stratified by site and screening HIV-1 RNA. Participants and investigators were not masked to group assignment, but allocation was concealed until after interventions were assigned. DXA scans were done at weeks 0, 48, and 96. The primary endpoint was mean percentage and absolute change in peripheral limb fat from baseline to week 96. We did intention-to-treat analyses of available data. This substudy is registered with ClinicalTrials.gov, number NCT01513122.

    FINDINGS: Between Aug 1, 2010, and July 10, 2011, we recruited 211 participants into the substudy. The intention-to-treat population comprised 102 participants in the N(t)RTI group and 108 participants in the raltegravir group, of whom 91 and 105 participants, respectively, reached 96 weeks. Mean percentage change in limb fat from baseline to week 96 was 16·8% (SD 32·6) in the N(t)RTI group and 28·0% (37·6) in the raltegravir group (mean difference 10·2%, 95% CI 0·1-20·4; p=0·048). Mean absolute change was 1·04 kg (SD 2·29) in the N(t)RTI group and 1·81 kg (2·50) in the raltegravir group (mean difference 0·6, 95% CI -0·1 to 1·3; p=0·10).

    INTERPRETATION: Our findings suggest that for people with virological failure of a first-line regimen containing efavirenz plus tenofovir and lamivudine or emtricitabine, the WHO-recommended switch to a ritonavir-boosted protease inhibitor plus zidovudine (a thymidine analogue nucleoside reverse transcriptase inhibitor) and lamivudine might come at the cost of peripheral lipoatrophy. Further study could help to define specific groups of people who might benefit from a switch to an N(t)RTI-sparing second-line ART regimen.

    FUNDING: The Kirby Institute and the Australian National Health and Medical Research Council.

    Matched MeSH terms: Viral Load
  10. Zain RM, Ibrahim N, Ismail S, Suppiah J, Mat Rahim NA, Thayan R
    Asian Pac J Trop Med, 2017 Jan;10(1):75-78.
    PMID: 28107870 DOI: 10.1016/j.apjtm.2016.12.005
    OBJECTIVE: To determine drug resistance mutations and the HIV-1 subtypes among antiretroviral treatment naive HIV-1 patients in Peninsular Malaysia.

    METHODS: A total of 45 samples from four hospitals that provide HIV viral load services were subjected to the amplification of the protease and two third of reverse transcriptase regions of the pol gene by RT-PCR and Sanger sequencing. Drug resistance mutation (DRM) interpretation reports the presence of mutations related to protease inhibitors (PIs), Nucleoside reverse-transcriptase inhibitors (NRTI) and Non-nucleoside reverse-transcriptase inhibitors (NNRTI) based on analysis using Stanford HIV database program.

    RESULTS: DRMs were identified in 35% of patients, among which 46.7% of them showed minor resistance to protease inhibitor with A71V and L10l were the commonest DRMs detected. About 21.4% and 50.0% of patients had mutations to NRTIs and NNRTIs, respectively. CRF01_AE was found to be the predominant HIV-1 subtype.

    CONCLUSIONS: These findings have served as an initial crucial data in determining the prevalence of transmitted HIV-1 drug resistance for the country. However, more samples from various parts of the country need to be accumulated and analyzed to provide overall HIV-1 drug resistance in the country.

    Matched MeSH terms: Viral Load
  11. Petoumenos K, Choi JY, Hoy J, Kiertiburanakul S, Ng OT, Boyd M, et al.
    Antivir Ther, 2017;22(8):659-668.
    PMID: 28291735 DOI: 10.3851/IMP3155
    BACKGROUND: In the era of effective antiretroviral treatment (ART) CD4:CD8 ratio is proposed as a potential marker for HIV-positive (HIV+) patients at increased risk for non-AIDS comorbidities. The current study aims to compare CD4:CD8 ratio between Asian and Caucasian HIV+ patients.

    METHODS: HIV+ patients from the Australian HIV Observational Database (AHOD) and the TREAT Asia HIV Observational Database (TAHOD) meeting specific criteria were included. In these analyses Asian and Caucasian status were defined by cohort. Factors associated with a low CD4:CD8 ratio (cutoff <0.2) prior to ART commencement, and with achieving a normal CD4:CD8 ratio (>1) at 12 and 24 months post ART commencement were assessed using logistic regression.

    RESULTS: There were 591 patients from AHOD and 2,620 patients from TAHOD who met the inclusion criteria. TAHOD patients had a significantly (P<0.001) lower odds of having a baseline (prior to ART initiation) CD4:CD8 ratio greater than 0.2. After 12 months of ART, AHOD patients were more than twice as likely to achieve a normal CD4:CD8 ratio compared to TAHOD patients (15% versus 6%). However, after adjustment for confounding factors there was no significant difference between cohorts in the odds of achieving a CD4:CD8 ratio >1 (P=0.475).

    CONCLUSIONS: We found a significantly lower CD4:CD8 ratio prior to commencing ART in TAHOD compared to AHOD even after adjusting for confounders. However, after adjustment, there was no significant difference between the cohorts in odds of achieving normal ratio. Baseline CD4+ and CD8+ counts seem to be the main driver for this difference between these two populations.

    Matched MeSH terms: Viral Load
  12. Kiertiburanakul S, Boettiger D, Ng OT, Van Kinh N, Merati TP, Avihingsanon A, et al.
    AIDS Res Ther, 2017;14:27.
    PMID: 28484509 DOI: 10.1186/s12981-017-0151-1
    BACKGROUND: Abacavir and rilpivirine are alternative antiretroviral drugs for treatment-naïve HIV-infected patients. However, both drugs are only recommended for the patients who have pre-treatment HIV RNA <100,000 copies/mL. In resource-limited settings, pre-treatment HIV RNA is not routinely performed and not widely available. The aims of this study are to determine factors associated with pre-treatment HIV RNA <100,000 copies/mL and to construct a model to predict this outcome.

    METHODS: HIV-infected adults enrolled in the TREAT Asia HIV Observational Database were eligible if they had an HIV RNA measurement documented at the time of ART initiation. The dataset was randomly split into a derivation data set (75% of patients) and a validation data set (25%). Factors associated with pre-treatment HIV RNA <100,000 copies/mL were evaluated by logistic regression adjusted for study site. A prediction model and prediction scores were created.

    RESULTS: A total of 2592 patients were enrolled for the analysis. Median [interquartile range (IQR)] age was 35.8 (29.9-42.5) years; CD4 count was 147 (50-248) cells/mm3; and pre-treatment HIV RNA was 100,000 (34,045-301,075) copies/mL. Factors associated with pre-treatment HIV RNA <100,000 copies/mL were age <30 years [OR 1.40 vs. 41-50 years; 95% confidence interval (CI) 1.10-1.80, p = 0.01], body mass index >30 kg/m2(OR 2.4 vs. <18.5 kg/m2; 95% CI 1.1-5.1, p = 0.02), anemia (OR 1.70; 95% CI 1.40-2.10, p 350 cells/mm3(OR 3.9 vs. <100 cells/mm3; 95% CI 2.0-4.1, p 2000 cells/mm3(OR 1.7 vs. <1000 cells/mm3; 95% CI 1.3-2.3, p 25 yielded the sensitivity of 46.7%, specificity of 79.1%, positive predictive value of 67.7%, and negative predictive value of 61.2% for prediction of pre-treatment HIV RNA <100,000 copies/mL among derivation patients.

    CONCLUSION: A model prediction for pre-treatment HIV RNA <100,000 copies/mL produced an area under the ROC curve of 0.70. A larger sample size for prediction model development as well as for model validation is warranted.

    Matched MeSH terms: Viral Load*
  13. Vignesh R, Swathirajan CR, Solomon SS, Shankar EM, Murugavel KG
    Indian J Med Microbiol, 2017 Apr-Jun;35(2):279-281.
    PMID: 28681821 DOI: 10.4103/ijmm.IJMM_16_163
    Immune reconstitution inflammatory syndrome (IRIS) continues to be a complication in HIV/tuberculosis (TB) co-infected patients initiating highly active antiretroviral therapy (HAART). The aim of this study was to evaluate the risk factors associated with developing IRIS to identify a possible biomarker to predict or diagnose IRIS in patients initiating HAART. A total of 175 HIV/TB co-infected patients initiating HAART were followed up longitudinally during September 2010 to May 2013 attending a HIV care clinic in Chennai. Patients were followed up longitudinally after HAART initiation and baseline demographic, laboratory parameters and treatment characteristics between patients with IRIS events and those without IRIS events were compared. Chi-square or Fisher's exact test for categorical variables and a Wilcoxon rank-sum test for continuous variables were performed using SPSS, version 12.0 software. Patients with IRIS had a significantly lower median baseline CD4+ T-cell count (P = 0.0039). There were no differences in terms of sex, CD4 T-cell %, plasma viral load, time interval between initiating ATT and HAART between the IRIS and non-IRIS patients. Low CD4+ T-cell count (<100 cells/μL) could be used as a marker to screen and monitor patients initiating HAART.
    Matched MeSH terms: Viral Load
  14. Okamura T, Tsujimura Y, Soma S, Takahashi I, Matsuo K, Yasutomi Y
    J Gen Virol, 2016 Dec;97(12):3413-3426.
    PMID: 27902330 DOI: 10.1099/jgv.0.000641
    Simian immunodeficiency virus (SIV) infection models in cynomolgus macaques are important for analysis of the pathogenesis of immunodeficiency virus and for studies on the efficacy of new vaccine candidates. However, very little is known about the pathogenesis of SIV or simian human immunodeficiency virus (SHIV) in cynomolgus macaques from different Asian countries. In the present study, we analysed the infectivity and pathogenicity of CCR5-tropic SIVmac and those of dual-tropic SHIV89.6P inoculated into cynomolgus macaques in Indonesian, Malaysian or Philippine origin. The plasma viral loads in macaques infected with either SIVmac239 or SHIV89.6P were maintained at high levels. CD4+ T cell levels in macaques infected with SIVmac239 gradually decreased. All of the macaques infected with SHIV89.6P showed greatly reduced CD4+ T-cell numbers within 6 weeks of infection. Eight of the 11 macaques infected with SIVmac239 were killed due to AIDS symptoms after 2-4.5 years, while four of the five macaques infected with SHIV89.6P were killed due to AIDS symptoms after 1-3.5 years. We also analysed cynomolgus macaques infected intrarectally with repeated low, medium or high doses of SIVmac239, SIVmac251 or SHIV89.6P. Infection was confirmed by quantitative RT-PCR at more than 5000, 300 and 500 TCID50 for SIVmac239, SIVmac251 and SHIV89.6P, respectively. The present study indicates that cynomolgus macaques of Asian origin are highly susceptible to SIVmac and SHIV infection by both intravenous and mucosal routes. These models will be useful for studies on virus pathogenesis, vaccination and therapeutics against human immunodeficiency virus/AIDS.
    Matched MeSH terms: Viral Load
  15. Ng KT, Chook JB, Oong XY, Chan YF, Chan KG, Hanafi NS, et al.
    Sci Rep, 2016 10 10;6:34855.
    PMID: 27721388 DOI: 10.1038/srep34855
    Human rhinovirus (HRV) is the major aetiology of respiratory tract infections. HRV viral load assays are available but limitations that affect accurate quantification exist. We developed a one-step Taqman assay using oligonucleotides designed based on a comprehensive list of global HRV sequences. The new oligonucleotides targeting the 5'-UTR region showed high PCR efficiency (E = 99.6%, R2 = 0.996), with quantifiable viral load as low as 2 viral copies/μl. Assay evaluation using an External Quality Assessment (EQA) panel yielded a detection rate of 90%. When tested on 315 human enterovirus-positive specimens comprising at least 84 genetically distinct HRV types/serotypes (determined by the VP4/VP2 gene phylogenetic analysis), the assay detected all HRV species and types, as well as other non-polio enteroviruses. A commercial quantification kit, which failed to detect any of the EQA specimens, produced a detection rate of 13.3% (42/315) among the clinical specimens. Using the improved assay, we showed that HRV sheds in the upper respiratory tract for more than a week following acute infection. We also showed that HRV-C had a significantly higher viral load at 2-7 days after the onset of symptoms (p = 0.001). The availability of such assay is important to facilitate disease management, antiviral development, and infection control.
    Matched MeSH terms: Viral Load*
  16. Tan SH, Ong KC, Perera D, Wong KT
    Antiviral Res, 2016 Aug;132:196-203.
    PMID: 27340013 DOI: 10.1016/j.antiviral.2016.04.015
    BACKGROUND: Enterovirus A71 (EV-A71) encephalomyelitis is an often fatal disease for which there is no specific treatment available. Passive immunization with a specific monoclonal antibody to EV-A71 was used on a murine model of EV-A71 encephalomyelitis to evaluate its therapeutic effectiveness before and after established central nervous system (CNS) infection.

    METHODS: Mice were intraperitoneally-infected with a mouse-adapted EV-A71 strain and treated with a dose of monoclonal antibody (MAb) daily for 3 days on day 1, 2 and 3 post-infection or for 3 days on 3, 4 and 5 post-infection. Treatment effectiveness was evaluated by signs of infection and survival rate. Histopathology and qPCR analyses were performed on mice sacrificed a day after completing treatment.

    RESULTS: In mock-treated mice, CNS infection was established from day 3 post-infection. All mice treated before established CNS infection, survived and recovered completely without CNS infection. All mice treated after established CNS infection survived with mild paralysis, and viral load and antigens/RNA at day 6 post-infection were significantly reduced.

    CONCLUSIONS: Passive immunization with our MAb could prevent CNS infection in mice if given early before the establishment of CNS infection. It could also ameliorate established CNS infection if optimal and repeated doses were given.

    Matched MeSH terms: Viral Load
  17. Ku NS, Jiamsakul A, Ng OT, Yunihastuti E, Cuong DD, Lee MP, et al.
    Medicine (Baltimore), 2016 Aug;95(32):e4570.
    PMID: 27512885 DOI: 10.1097/MD.0000000000004570
    Elevated CD8 counts with combination antiretroviral therapy (cART) initiation may be an early warning indicator for future treatment failure. Thus, we investigated whether elevated CD8 counts were associated with virological failure (VF) in the first 4 years of cART in Asian HIV-infected patients in a multicenter regional cohort.We included patients from the TREAT Asia HIV Observational Database (TAHOD). Patients were included in the analysis if they started cART between 1996 and 2013 with at least one CD8 measurement within 6 months prior to cART initiation and at least one CD8 and viral load (VL) measurement beyond 6 months after starting cART. We defined VF as VL ≥400 copies/mL after 6 months on cART. Elevated CD8 was defined as CD8 ≥1200 cells/μL. Time to VF was modeled using Cox regression analysis, stratified by site.In total, 2475 patients from 19 sites were included in this analysis, of whom 665 (27%) experienced VF in the first 4 years of cART. The overall rate of VF was 12.95 per 100 person-years. In the multivariate model, the most recent elevated CD8 was significantly associated with a greater hazard of VF (HR = 1.35, 95% CI 1.14-1.61; P = 0.001). However, the sensitivity analysis showed that time-lagged CD8 measured at least 6 months prior to our virological endpoint was not statistically significant (P = 0.420).This study indicates that the relationship between the most recent CD8 count and VF was possibly due to the CD8 cells reacting to the increase in VL rather than causing the VL increase itself. However, CD8 levels may be a useful indicator for VF in HIV-infected patients after starting cART.
    Matched MeSH terms: Viral Load/drug effects
  18. Clayton BA, Middleton D, Arkinstall R, Frazer L, Wang LF, Marsh GA
    PLoS Negl Trop Dis, 2016 06;10(6):e0004775.
    PMID: 27341030 DOI: 10.1371/journal.pntd.0004775
    Person-to-person transmission is a key feature of human Nipah virus outbreaks in Bangladesh. In contrast, in an outbreak of Nipah virus in Malaysia, people acquired infections from pigs. It is not known whether this important epidemiological difference is driven primarily by differences between NiV Bangladesh (NiV-BD) and Malaysia (NiV-MY) at a virus level, or by environmental or host factors. In a time course study, ferrets were oronasally exposed to equivalent doses of NiV-BD or NiV-MY. More rapid onset of productive infection and higher levels of virus replication in respiratory tract tissues were seen for NiV-BD compared to NiV-MY, corroborating our previous report of increased oral shedding of NiV-BD in ferrets and suggesting a contributory mechanism for increased NiV-BD transmission between people compared to NiV-MY. However, we recognize that transmission occurs within a social and environmental framework that may have an important and differentiating role in NiV transmission rates. With this in mind, ferret-to-ferret transmission of NiV-BD and NiV-MY was assessed under differing viral exposure conditions. Transmission was not identified for either virus when naïve ferrets were cohoused with experimentally-infected animals. In contrast, all naïve ferrets developed acute infection following assisted and direct exposure to oronasal fluid from animals that were shedding either NiV-BD or NiV-MY. Our findings for ferrets indicate that, although NiV-BD may be shed at higher levels than NiV-MY, transmission risk may be equivalently low under exposure conditions provided by cohabitation alone. In contrast, active transfer of infected bodily fluids consistently results in transmission, regardless of the virus strain. These observations suggest that the risk of NiV transmission is underpinned by social and environmental factors, and will have practical implications for managing transmission risk during outbreaks of human disease.
    Matched MeSH terms: Viral Load
  19. Simarmata D, Ng DC, Kam YW, Lee B, Sum MS, Her Z, et al.
    Sci Rep, 2016 05 16;6:26097.
    PMID: 27180811 DOI: 10.1038/srep26097
    Chikungunya fever (CHIKF) is a global infectious disease which can affect a wide range of age groups. The pathological and immunological response upon Chikungunya virus (CHIKV) infection have been reported over the last few years. However, the clinical profile and immune response upon CHIKV infection in children remain largely unknown. In this study, we analyzed the clinical and immunological response, focusing on the cytokine/chemokine profile in a CHIKV-infected pediatric cohort from Sarawak, Malaysia. Unique immune mediators triggered upon CHIKV infection were identified through meta-analysis of the immune signatures between this pediatric group and cohorts from previous outbreaks. The data generated from this study revealed that a broad spectrum of cytokines/chemokines is up-regulated in a sub-group of virus-infected children stratified according to their viremic status during hospitalization. Furthermore, different immune mediator profiles (the levels of pro-inflammatory cytokines, chemokines and growth and other factors) were observed between children and adults. This study gives an important insight to understand the immune response of CHIKV infection in children and would aid in the development of better prognostics and clinical management for children.
    Matched MeSH terms: Viral Load*
  20. Jiamsakul A, Kerr SJ, Ng OT, Lee MP, Chaiwarith R, Yunihastuti E, et al.
    Trop Med Int Health, 2016 May;21(5):662-74.
    PMID: 26950901 DOI: 10.1111/tmi.12690
    OBJECTIVES: Treatment interruptions (TIs) of combination antiretroviral therapy (cART) are known to lead to unfavourable treatment outcomes but do still occur in resource-limited settings. We investigated the effects of TI associated with adverse events (AEs) and non-AE-related reasons, including their durations, on treatment failure after cART resumption in HIV-infected individuals in Asia.

    METHODS: Patients initiating cART between 2006 and 2013 were included. TI was defined as stopping cART for >1 day. Treatment failure was defined as confirmed virological, immunological or clinical failure. Time to treatment failure during cART was analysed using Cox regression, not including periods off treatment. Covariables with P < 0.10 in univariable analyses were included in multivariable analyses, where P < 0.05 was considered statistically significant.

    RESULTS: Of 4549 patients from 13 countries in Asia, 3176 (69.8%) were male and the median age was 34 years. A total of 111 (2.4%) had TIs due to AEs and 135 (3.0%) had TIs for other reasons. Median interruption times were 22 days for AE and 148 days for non-AE TIs. In multivariable analyses, interruptions >30 days were associated with failure (31-180 days HR = 2.66, 95%CI (1.70-4.16); 181-365 days HR = 6.22, 95%CI (3.26-11.86); and >365 days HR = 9.10, 95% CI (4.27-19.38), all P < 0.001, compared to 0-14 days). Reasons for previous TI were not statistically significant (P = 0.158).

    CONCLUSIONS: Duration of interruptions of more than 30 days was the key factor associated with large increases in subsequent risk of treatment failure. If TI is unavoidable, its duration should be minimised to reduce the risk of failure after treatment resumption.

    Matched MeSH terms: Viral Load
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