Displaying publications 101 - 120 of 137 in total

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  1. Lim A, Tan D, Price P, Kamarulzaman A, Tan HY, James I, et al.
    AIDS, 2007 Jul 31;21(12):1525-34.
    PMID: 17630546
    To examine the relationships between blood CD4 natural regulatory T (Treg) cells, plasma HIV RNA level, CD4 T-cell count and immune activation in untreated HIV-infected patients and immunodeficient patients beginning antiretroviral therapy (ART), using a novel phenotype to define Treg cells (CD25CD127CD4). Data were compared with established Treg cell markers (FoxP3, CTLA-4 and GITR).
    Matched MeSH terms: Viral Load
  2. Tan EL, Selvaratnam G, Kananathan R, Sam CK
    BMC Cancer, 2006;6:227.
    PMID: 16995954
    Nasopharyngeal carcinoma (NPC) is a common epithelial neoplasm among the Chinese populations in Southern China and South East Asia. Epstein-Barr virus (EBV) is known to be an important etiologic agent of NPC and the viral gene products are frequently detected in NPC tissues along with elevated antibody titres to the viral proteins (VCA and EA) in a majority of patients. Elevated plasma EBV DNA load is regarded as an important marker for the presence of the disease and for the monitoring of disease progression. However, other serum/plasma parameters such as the levels of certain interleukins and growth factors have also been implicated in NPC. The objectives of the present study are, 1) to investigate the correlations between plasma EBV DNA load and the levels of interleukin (IL)-6, IL-10, TGF-beta1 and SCF (steel factor) and 2) to relate these parameters to the stages of NPC and the effect of treatment.
    Matched MeSH terms: Viral Load
  3. Chiam CW, Chan YF, Loong SK, Yong SS, Hooi PS, Sam IC
    Diagn Microbiol Infect Dis, 2013 Oct;77(2):133-7.
    PMID: 23886793 DOI: 10.1016/j.diagmicrobio.2013.06.018
    Quantitative real-time polymerase chain reaction (qRT-PCR) is useful for diagnosis and studying virus replication. We developed positive- and negative-strand qRT-PCR assays to detect nsP3 of chikungunya virus (CHIKV), a positive-strand RNA alphavirus that causes epidemic fever, rash, and arthritis. The positive- and negative-strand qRT-PCR assays had limits of quantification of 1 and 3 log10 RNA copies/reaction, respectively. Compared to a published E1 diagnostic assay using 30 laboratory-confirmed clinical samples, the positive-strand nsP3 qRT-PCR assay had higher R(2) and efficiency and detected more positive samples. Peak viral load of 12.9 log(10) RNA copies/mL was reached on day 2 of illness, and RNA was detectable up to day 9, even in the presence of anti-CHIKV IgM. There was no correlation between viral load and persistent arthralgia. The positive-strand nsP3 assay is suitable for diagnosis, while the negative-strand nsP3 assay, which uses tagged primers to increase specificity, is useful for study of active viral replication kinetics.
    Matched MeSH terms: Viral Load
  4. Boettiger DC, An VT, Kumarasamy N, Azwa I, Sudjaritruk T, Truong KH, et al.
    J Acquir Immune Defic Syndr, 2022 Jun 01;90(2):193-200.
    PMID: 35125475 DOI: 10.1097/QAI.0000000000002931
    OBJECTIVE: To assess recent trends in the monitoring of antiretroviral therapy (ART) and detection of ART failure in adult and pediatric HIV clinics.

    METHODS: We used data collected from 21 adult and 17 pediatric sites (across 13 and 6 countries/territories, respectively) in the International Epidemiology Databases to Evaluate AIDS - Asia-Pacific cohort. ART failure was defined as viral, immune, or clinical consistent with WHO guidelines.

    RESULTS: A total of 8567 adults and 6149 children contributed data. Frequency of CD4 count monitoring declined between 2010 and 2019 among adult sites (from 1.93 to 1.06 tests/person per year, a 45.1% decline) and pediatric sites (from 2.16 to 0.86 testsperson per year, a 60.2% decline), whereas rates of viral load monitoring remained relatively stable. The proportion of adult and pediatric treatment failure detected as immune failure declined (from 73.4% to 50.0% and from 45.8% to 23.1%, respectively), whereas the proportion of failure detected as viral failure increased (from 7.8% to 25.0% and from 45.8% to 76.9%, respectively). The proportion of ART failure detected as clinical failure remained stable among adult and pediatric sites. The largest shifts in ART monitoring and failure type occurred in lower middle-income countries.

    CONCLUSIONS: Although viral failure in our Asian cohort now comprises a larger portion of ART failure than in prior years, the diagnostic characteristics of immune and clinical failure, and recommendations on their management, remain important inclusions for regional ART guidelines.

    Matched MeSH terms: Viral Load
  5. Balakrishnan P, Saravanan S, Vignesh R, Shankar EM
    Indian J Med Res, 2023 Nov 01;158(5&6):447-450.
    PMID: 38063301 DOI: 10.4103/ijmr.ijmr_1616_23
    Matched MeSH terms: Viral Load
  6. Tan TS, Sharifah Syed Hassan, Yap WB
    Sains Malaysiana, 2016;45:787-793.
    The use of cell lines such as Madin-Darby Canine Kidney (MDCK) and African Green Monkey Kidney (Vero) cells in
    influenza vaccine production is much advocated presently as a safer alternative to chicken embryonated eggs. It is
    thus essential to understand the influenza virus replication patterns in these cell lines prior to utilizing them in vaccine
    production. The infectivity of avian influenza A virus (A/Chicken/Malaysia/5858/2004) H5N1 in MDCK and Vero cell
    lines was first assessed by comparing the cytopathic effect (CPE) caused by the virus infection. The viral loads in both
    of the infected media and cells were also compared. The results showed that both of the MDCK and Vero cells began to
    exhibit significant CPE (p<0.05) after 48 h post-infection (h p.i). The MDCK cell line was more susceptible to the virus
    infection compared to Vero cell line throughout the incubation period. A higher viral load was also detected in the host
    cells compared to their respective culturing media. Interestingly, after reaching its maximum titer at 48 h p.i, the viral
    load in MDCK cells declined meanwhile the viral load in Vero cells increased gradually and peaked at 120 h p.i. Overall,
    both cell lines support efficient H5N1 virus replication. While the peak viral loads measured in the two cell lines did
    not differ much, a more rapid replication was observed in the infected MDCK samples. The finding showed that MDCK
    cell line might serve as a more time-saving and cost-effective cell culture-based system compared to Vero cell line for
    influenza vaccine production.
    Matched MeSH terms: Viral Load
  7. Prasad AN, Woolsey C, Geisbert JB, Agans KN, Borisevich V, Deer DJ, et al.
    J Infect Dis, 2020 05 11;221(Suppl 4):S436-S447.
    PMID: 32022850 DOI: 10.1093/infdis/jiz613
    BACKGROUND: The henipaviruses, Hendra virus (HeV) and Nipah virus (NiV), are capable of causing severe and often lethal respiratory and/or neurologic disease in animals and humans. Given the sporadic nature of henipavirus outbreaks, licensure of vaccines and therapeutics for human use will likely require demonstration of efficacy in animal models that faithfully reproduce the human condition. Currently, the African green monkey (AGM) best mimics human henipavirus-induced disease.

    METHODS: The pathogenic potential of HeV and both strains of NiV (Malaysia, Bangladesh) was assessed in cynomolgus monkeys and compared with henipavirus-infected historical control AGMs. Multiplex gene and protein expression assays were used to compare host responses.

    RESULTS: In contrast to AGMs, in which henipaviruses cause severe and usually lethal disease, HeV and NiVs caused only mild or asymptomatic infections in macaques. All henipaviruses replicated in macaques with similar kinetics as in AGMs. Infection in macaques was associated with activation and predicted recruitment of cytotoxic CD8+ T cells, Th1 cells, IgM+ B cells, and plasma cells. Conversely, fatal outcome in AGMs was associated with aberrant innate immune signaling, complement dysregulation, Th2 skewing, and increased secretion of MCP-1.

    CONCLUSION: The restriction factors identified in macaques can be harnessed for development of effective countermeasures against henipavirus disease.

    Matched MeSH terms: Viral Load
  8. Mohd A, Zainal N, Tan KK, AbuBakar S
    Sci Rep, 2019 10 04;9(1):14336.
    PMID: 31586088 DOI: 10.1038/s41598-019-50674-3
    Zika virus (ZIKV) infection is a serious public health concern. ZIKV infection has been associated with increased occurrences of microcephaly among newborns and incidences of Guillain-Barré syndrome among adults. No specific therapeutics or vaccines are currently available to treat and protect against ZIKV infection. Here, a plant-secreted phytoalexin, resveratrol (RES), was investigated for its ability to inhibit ZIKV replication in vitro. Several RES treatment regimens were used. The ZIKV titers of mock- and RES-treated infected cell cultures were determined using the focus-forming assay and the Zika mRNA copy number as determined using qRT-PCR. Our results suggested that RES treatment reduced ZIKV titers in a dose-dependent manner. A reduction of >90% of virus titer and ZIKV mRNA copy number was achieved when infected cells were treated with 80 µM of RES post-infection. Pre-incubation of the virus with 80 µM RES showed >30% reduction in ZIKV titers and ZIKV mRNA copy number, implying potential direct virucidal effects of RES against the virus. The RES treatment reduced >70% virus titer in the anti-adsorption assay, suggesting the possibility that RES also interferes with ZIKV binding. However, there was no significant decrease in ZIKV titer when a short-period of RES treatment was applied to cells before ZIKV infection (pre-infection) and after the virus bound to the cells (virus internalization inhibition), implying that RES acts through its continuous presence in the cell cultures after virus infection. Overall, our results suggested that RES exhibited direct virucidal activity against ZIKV and possessed anti-ZIKV replication properties, highlighting the need for further exploration of RES as a potential antiviral molecule against ZIKV infection.
    Matched MeSH terms: Viral Load
  9. 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
  10. Tan SS, Abu Hassan MR, Abdullah A, Ooi BP, Korompis T, Merican MI
    J Viral Hepat, 2010 Jun;17(6):410-8.
    PMID: 19758272 DOI: 10.1111/j.1365-2893.2009.01191.x
    Chronic hepatitis C is associated with increased morbidity and mortality in persons undergoing haemodialysis. This single-arm, open-label clinical trial investigated the safety and efficacy of an escalating dosage regimen of pegylated interferon (PEG-IFN) alpha-2b in this patient population. Patients with chronic hepatitis C who were undergoing haemodialysis began treatment with PEG-IFN alpha-2b at a dose of 0.5 microg/kg/week, which was increased every 4 weeks to a maximum of 1 microg/kg/week. Treatment duration was 24 weeks for patients with genotype (G) 2 or 3 infection and 48 weeks for patients with G1 infection. The primary end point was sustained virological response (SVR). Of 46 patients screened, 34 (G1: 70.6%; G3: 29.4%) were treated and 23 (67.6%) completed treatment. Overall, 85.3% of patients experienced early virological response, 52.9% experienced end-of-treatment response, and 50% attained SVR, with a trend toward higher SVR rates in G3 compared with G1 patients (80%vs 37.5%; P = 0.06). Anaemia was the main reason for discontinuation of treatment. Patients with chronic hepatitis C who are undergoing haemodialysis can be successfully treated with an escalating dosage regimen of PEG-IFN alpha-2b monotherapy. G3-infected patients can attain high rates of SVR with only 24 weeks of therapy.
    Matched MeSH terms: Viral Load
  11. 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*
  12. 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
  13. Mehrbod P, Hair-Bejo M, Tengku Ibrahim TA, Omar AR, El Zowalaty M, Ajdari Z, et al.
    Int J Mol Med, 2014 Jul;34(1):61-73.
    PMID: 24788303 DOI: 10.3892/ijmm.2014.1761
    Influenza A virus is one of the most important health risks that lead to significant respiratory infections. Continuous antigenic changes and lack of promising vaccines are the reasons for the unsuccessful treatment of influenza. Statins are pleiotropic drugs that have recently served as anti-influenza agents due to their anti-inflammatory activity. In this study, the effect of simvastatin on influenza A-infected cells was investigated. Based on the MTT cytotoxicity test, hemagglutination (HA) assay and qPCR it was found that simvastatin maintained cell viability and decreased the viral load significantly as compared to virus-inoculated cells. The expression of important pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-6 and interferon-γ), which was quantified using ELISA showed that simvastatin decreased the expression of pro-inflammatory cytokines to an average of 2-fold. Furthermore, the modulation of actin filament polymerization was determined using rhodamine staining. Endocytosis and autophagy processes were examined by detecting Rab and RhoA GTPase protein prenylation and LC3 lipidation using western blotting. The results showed that inhibiting GTPase and LC3 membrane localization using simvastatin inhibits influenza replication. Findings of this study provide evidence that modulation of RhoA, Rabs and LC3 may be the underlying mechanisms for the inhibitory effects of simvastatin as an anti-influenza compound.
    Matched MeSH terms: Viral Load/drug effects
  14. DeBuysscher BL, Scott D, Marzi A, Prescott J, Feldmann H
    Vaccine, 2014 May 07;32(22):2637-44.
    PMID: 24631094 DOI: 10.1016/j.vaccine.2014.02.087
    BACKGROUND: Nipah virus (NiV), a zoonotic pathogen causing severe respiratory illness and encephalitis in humans, emerged in Malaysia in 1998 with subsequent outbreaks on an almost annual basis since 2001 in parts of the Indian subcontinent. The high case fatality rate, human-to-human transmission, wide-ranging reservoir distribution and lack of licensed intervention options are making NiV a serious regional and potential global public health problem. The objective of this study was to develop a fast-acting, single-dose NiV vaccine that could be implemented in a ring vaccination approach during outbreaks.

    METHODS: In this study we have designed new live-attenuated vaccine vectors based on recombinant vesicular stomatitis viruses (rVSV) expressing NiV glycoproteins (G or F) or nucleoprotein (N) and evaluated their protective efficacy in Syrian hamsters, an established NiV animal disease model. We further characterized the humoral immune response to vaccination in hamsters using ELISA and neutralization assays and performed serum transfer studies.

    RESULTS: Vaccination of Syrian hamsters with a single dose of the rVSV vaccine vectors resulted in strong humoral immune responses with neutralizing activities found only in those animals vaccinated with rVSV expressing NiV G or F proteins. Vaccinated animals with neutralizing antibody responses were completely protected from lethal NiV disease, whereas animals vaccinated with rVSV expressing NiV N showed only partial protection. Protection of NiV G or F vaccinated animals was conferred by antibodies, most likely the neutralizing fraction, as demonstrated by serum transfer studies. Protection of N-vaccinated hamsters was not antibody-dependent indicating a role of adaptive cellular responses for protection.

    CONCLUSIONS: The rVSV vectors expressing Nipah virus G or F are prime candidates for new 'emergency vaccines' to be utilized for NiV outbreak management.

    Matched MeSH terms: Viral Load
  15. Rothan HA, Buckle MJ, Ammar YA, Mohammadjavad P, Shatrah O, Noorsaadah AR, et al.
    Trop Biomed, 2013 Dec;30(4):681-90.
    PMID: 24522138
    Various clinical symptoms are caused by dengue virus ranging from mild fever to severe hemorrhagic fever while there is no successful anti-dengue therapeutics available. Among different strategies towards identifying and developing anti-dengue therapeutics, testing anti-dengue properties of known drugs could represent an efficient strategy for which information of its medical approval, toxicity and side effects is readily available. In this study, we evaluated the antiviral activity of some medical compounds towards dengue NS2B-NS3 protease (DENV2 NS2B-NS3pro) as a target to inhibit dengue virus replication. Mefenamic acid, a non-steroid anti inflammatory drug and doxycycline, a derivative antibiotic of tetracycline both showed significant inhibition potential against DENV2 NS2B-NS3pro Ki values 32 ± 2 μM and 55 ± 5 μM respectively. The effective cytotoxic concentrations of 50% (CC50) against Vero cells were evaluated for mefenamic acid (150 ± 5 μM) and doxycycline (125 ± 4 μM). Concentrations lower than CC50 were used to test the inhibition potential of these compounds against DENV2 replication in Vero cells. The results showed significant reduction in viral load after applying mefenamic acid and doxycyline in concentration dependent manner. Mefenamic acid reduced viral RNA at EC50 of 32 ± 4 μM whilst doxycycline EC50 was 40 ± 3 μM. Mefenamic acid showed higher selectivity against dengue virus replication in vitro compared to doxycycline. These findings underline the need for further experimental and clinical studies on these drugs utilizing its anti-dengue and anti-inflammatory activities to attenuate the clinical symptoms of dengue infection.
    Matched MeSH terms: Viral Load
  16. Naing C, Sitt T, Aung AT, Aung K
    Medicine (Baltimore), 2015 Jul;94(30):e1234.
    PMID: 26222859 DOI: 10.1097/MD.0000000000001234
    In Myanmar, hepatitis C virus (HCV) infection prevalence is 2%. A combination therapy of pegylated interferon alfa-2a and ribavirin (PEG-IFNa/RBV) is a standard treatment, but the effect of this antiviral therapy needs evaluation as to determine the efficacy and safety of dual PEG-IFNa/RBV therapy in treating patients infected with HCV in Myanmar.This was a retrospective analysis of data from a single clinic exclusively for gastrointestinal diseases in Yangon, Myanmar. We assessed treatment responses at the defined time points and stratified by genotypes of HCV. We also determined incidences of adverse events (AEs). We investigated independent predictors of sustained virologic response (SVR) in the participants.A total of 362 HCV-infected cases were included in this study. The majority were females (51.7%) with mean age of 47.12 years (±11.6) and noncirrhosis patients (82%). Rapid virologic response (RVR), early virologic response (EVR), end of treatment response (ETR), and SVR 24 weeks after completion of the dual treatment were 50.3% (178/362), 88% (314/357), 80.1% (286/357), and 85.6% (167/195), respectively. The most frequently reported AEs were nausea/anorexia (72.8%) and flu-like symptoms (62.4%). In multivariate analysis, 4 factors were independently associated with SVR; SVR to genotype 3 (odds ratio [OR] 2.4, 95% CI: 1.24-4.62), EVR (OR 0.54, 95% CI: 0.3-0.95), and duration of treatment (OR 1.52, 95% CI: 1.18-1.98). Study limitations were acknowledged.The efficacy and safety of the dual therapy in treating HCV-infected patient in Myanmar was acceptable. We recommend a prospective randomized control trial looking at duration of therapy and rates of achieving SVR, which could significantly impact the care of HCV-infected patients in Myanmar and perhaps other countries as well.
    Matched MeSH terms: Viral Load/drug effects*
  17. 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
  18. Lee JH, Hammoud DA, Cong Y, Huzella LM, Castro MA, Solomon J, et al.
    J Infect Dis, 2020 05 11;221(Suppl 4):S419-S430.
    PMID: 31687756 DOI: 10.1093/infdis/jiz502
    Nipah virus (NiV) is an emerging virus associated with outbreaks of acute respiratory disease and encephalitis. To develop a neurological model for NiV infection, we exposed 6 adult African green monkeys to a large-particle (approximately 12 μm) aerosol containing NiV (Malaysian isolate). Brain magnetic resonance images were obtained at baseline, every 3 days after exposure for 2 weeks, and then weekly until week 8 after exposure. Four of six animals showed abnormalities reminiscent of human disease in brain magnetic resonance images. Abnormalities ranged from cytotoxic edema to vasogenic edema. The majority of lesions were small infarcts, and a few showed inflammatory or encephalitic changes. Resolution or decreased size in some lesions resembled findings reported in patients with NiV infection. Histological lesions in the brain included multifocal areas of encephalomalacia, corresponding to known ischemic foci. In other regions of the brain there was evidence of vasculitis, with perivascular infiltrates of inflammatory cells and rare intravascular fibrin thrombi. This animal model will help us better understand the acute neurological features of NiV infection and develop therapeutic approaches for managing disease caused by NiV infection.
    Matched MeSH terms: Viral Load
  19. HIV-CAUSAL Collaboration, Ray M, Logan R, Sterne JA, Hernández-Díaz S, Robins JM, et al.
    AIDS, 2010 Jan 02;24(1):123-37.
    PMID: 19770621 DOI: 10.1097/QAD.0b013e3283324283
    OBJECTIVE: To estimate the effect of combined antiretroviral therapy (cART) on mortality among HIV-infected individuals after appropriate adjustment for time-varying confounding by indication.

    DESIGN: A collaboration of 12 prospective cohort studies from Europe and the United States (the HIV-CAUSAL Collaboration) that includes 62 760 HIV-infected, therapy-naive individuals followed for an average of 3.3 years. Inverse probability weighting of marginal structural models was used to adjust for measured confounding by indication.

    RESULTS: Two thousand and thirty-nine individuals died during the follow-up. The mortality hazard ratio was 0.48 (95% confidence interval 0.41-0.57) for cART initiation versus no initiation. In analyses stratified by CD4 cell count at baseline, the corresponding hazard ratios were 0.29 (0.22-0.37) for less than 100 cells/microl, 0.33 (0.25-0.44) for 100 to less than 200 cells/microl, 0.38 (0.28-0.52) for 200 to less than 350 cells/microl, 0.55 (0.41-0.74) for 350 to less than 500 cells/microl, and 0.77 (0.58-1.01) for 500 cells/microl or more. The estimated hazard ratio varied with years since initiation of cART from 0.57 (0.49-0.67) for less than 1 year since initiation to 0.21 (0.14-0.31) for 5 years or more (P value for trend <0.001).

    CONCLUSION: We estimated that cART halved the average mortality rate in HIV-infected individuals. The mortality reduction was greater in those with worse prognosis at the start of follow-up.

    Matched MeSH terms: Viral Load
  20. Cain LE, Phillips A, Lodi S, Sabin C, Bansi L, Justice A, et al.
    AIDS, 2012 Aug 24;26(13):1691-705.
    PMID: 22546987
    OBJECTIVE: To compare regimens consisting of either efavirenz or nevirapine and two or more nucleoside reverse transcriptase inhibitors (NRTIs) among HIV-infected, antiretroviral-naive, and AIDS-free individuals with respect to clinical, immunologic, and virologic outcomes.

    DESIGN: Prospective studies of HIV-infected individuals in Europe and the US included in the HIV-CAUSAL Collaboration.

    METHODS: Antiretroviral therapy-naive and AIDS-free individuals were followed from the time they started an NRTI, efavirenz or nevirapine, classified as following one or both types of regimens at baseline, and censored when they started an ineligible drug or at 6 months if their regimen was not yet complete. We estimated the 'intention-to-treat' effect for nevirapine versus efavirenz regimens on clinical, immunologic, and virologic outcomes. Our models included baseline covariates and adjusted for potential bias introduced by censoring via inverse probability weighting.

    RESULTS: A total of 15 336 individuals initiated an efavirenz regimen (274 deaths, 774 AIDS-defining illnesses) and 8129 individuals initiated a nevirapine regimen (203 deaths, 441 AIDS-defining illnesses). The intention-to-treat hazard ratios [95% confidence interval (CI)] for nevirapine versus efavirenz regimens were 1.59 (1.27, 1.98) for death and 1.28 (1.09, 1.50) for AIDS-defining illness. Individuals on nevirapine regimens experienced a smaller 12-month increase in CD4 cell count by 11.49 cells/μl and were 52% more likely to have virologic failure at 12 months as those on efavirenz regimens.

    CONCLUSIONS: Our intention-to-treat estimates are consistent with a lower mortality, a lower incidence of AIDS-defining illness, a larger 12-month increase in CD4 cell count, and a smaller risk of virologic failure at 12 months for efavirenz compared with nevirapine.

    Matched MeSH terms: Viral Load
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