Displaying publications 301 - 320 of 864 in total

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  1. Machain-Williams C, Reyes-Solis GC, Blitvich BJ, Laredo-Tiscareño V, Dzul-Rosado AR, Kim S, et al.
    Viral Immunol, 2023 Mar;36(2):101-109.
    PMID: 36862827 DOI: 10.1089/vim.2022.0110
    Dengue virus (DENV) is the etiological agent of dengue, the most important mosquito-transmitted viral disease of humans worldwide. Enzyme-linked immunosorbent assays (ELISAs) designed to detect DENV IgM are commonly used for dengue diagnosis. However, DENV IgM is not reliably detected until ≥4 days after illness onset. Reverse transcription-polymerase chain reaction (RT-PCR) can diagnose early dengue but requires specialized equipment, reagents, and trained personnel. Additional diagnostic tools are needed. Limited work has been performed to determine whether IgE-based assays can be used for the early detection of vector-borne viral diseases, including dengue. In this study, we determined the efficacy of a DENV IgE capture ELISA for the detection of early dengue. Sera were collected within the first 4 days of illness onset from 117 patients with laboratory-confirmed dengue, as determined by DENV-specific RT-PCR. The serotypes responsible for the infections were DENV-1 and DENV-2 (57 and 60 patients, respectively). Sera were also collected from 113 dengue-negative individuals with febrile illness of undetermined etiology and 30 healthy controls. The capture ELISA detected DENV IgE in 97 (82.9%) confirmed dengue patients and none of the healthy controls. There was a high false positivity rate (22.1%) among the febrile non-dengue patients. In conclusion, we provide evidence that IgE capture assays have the potential to be explored for early diagnosis of dengue, but further research is necessary to address the possible false positivity rate among patients with other febrile illnesses.
    Matched MeSH terms: Dengue Virus/immunology
  2. Appanna R, Huat TL, See LL, Tan PL, Vadivelu J, Devi S
    Clin Vaccine Immunol, 2007 Aug;14(8):969-77.
    PMID: 17567768
    Dengue virus infections are a major cause of morbidity and mortality in tropical and subtropical areas in the world. Attempts to develop effective vaccines have been hampered by the lack of understanding of the pathogenesis of the disease and the absence of suitable experimental models for dengue viral infection. The magnitude of T-cell responses has been reported to correlate with dengue disease severity. Sixty Malaysian adults with dengue viral infections were investigated for their dengue virus-specific T-cell responses to 32 peptides antigens from the structural and nonstructural regions from a dengue virus isolate. Seventeen different peptides from the C, E, NS2B, NS3, NS4A, NS4B, and NS5 regions were found to evoke significant responses in a gamma interferon enzyme-linked immunospot (ELISPOT) assay of samples from 13 selected patients with dengue fever (DF) and dengue hemorrhagic fever (DHF). NS3 and predominantly NS3(422-431) were found to be important T-cell targets. The highest peaks of T-cell responses observed were in responses to NS3(422-431) and NS5(563-571) in DHF patients. We also found almost a sevenfold increase in T-cell response in three DHF patients compared to three DF patient responses to peptide NS3(422-431). A large number of patients' T cells also responded to the NS2B(97-106) region. The ELISPOT analyses also revealed high frequencies of T cells that recognize both serotype-specific and cross-reactive dengue virus antigens in patients with DHF.
    Matched MeSH terms: Dengue/immunology*; Dengue/virology; Dengue Virus/immunology*; Severe Dengue/immunology*; Severe Dengue/virology
  3. Lee MF, Anasir MI, Poh CL
    J Pharm Sci, 2024 Mar;113(3):587-595.
    PMID: 38103687 DOI: 10.1016/j.xphs.2023.12.009
    Dengue presents a major public health concern in over 100 countries due to the absence of an effective vaccine and antiviral therapy against all four dengue virus (DENV) serotypes. Several antiviral peptides were previously reported to inhibit at least three or all four DENV serotypes. Chemical modifications such as d-amino acid substitutions, polyethylene glycol (PEG)ylation, and cyclization could be applied to peptides to improve their biological activities and stability in serum. The PEGylated peptide 3 (PEG-P3) was identified to be the most promising antiviral candidate as it demonstrated good inhibitory effects against all four DENV serotypes during the pre- and post-infection stages, Based on the RP-HPLC and LC/MS analysis, peptide 4 was identified to be more stable in human serum than peptide 3, with 78.9 % and 41.6 % of the peptides remaining after 72 h of incubation in human serum, respectively. Both peptides were also able to retain their antiviral activities against specific DENV serotypes after 72 h incubation in human serum. PEG-P3 was found to be more stable than the unmodified peptide 3 with 89.4 % of PEG-P3 remaining in the human serum after 72 h of incubation. PEG-P3 was able to retain its inhibitory effects against DENV-1 to 4 after 72 h of incubation in human serum. This study provided insights into the antiviral activities and stabilities of the unmodified and chemically modified peptides in human serum.
    Matched MeSH terms: Dengue Virus*
  4. Dhanoa A, Hassan SS, Jahan NK, Reidpath DD, Fatt QK, Ahmad MP, et al.
    Infect Dis Poverty, 2018 Jan 16;7(1):1.
    PMID: 29335021 DOI: 10.1186/s40249-017-0384-1
    BACKGROUND: The frequency and magnitude of dengue epidemics continue to increase exponentially in Malaysia, with a shift in the age range predominance toward adults and an expansion to rural areas. Despite this, information pertaining to the extent of transmission of dengue virus (DENV) in the rural community is lacking. This community-based pilot study was conducted to establish DENV seroprevalence amongst healthy adults in a rural district in Southern Malaysia, and to identify influencing factors.

    METHODS: In this study undertaken between April and May 2015, a total of 277 adult participants were recruited from households across three localities in the Sungai Segamat subdistrict in Segamat district. Sera were tested for immunoglobulin G (IgG) (Panbio® Dengue Indirect IgG ELISA/high-titer capture) and immunoglobulin M (IgM) (Panbio®) antibodies. The plaque reduction neutralization test (PRNT) was conducted on random samples of IgG-positive sera for further confirmation. Medical history and a recall of previous history of dengue were collected through interviews, whereas sociodemographic information was obtained from an existing database.

    RESULTS: The overall seroprevalence for DENV infection was 86.6% (240/277) (95% CI: 83-91%). Serological evidence of recent infection (IgM/high-titer capture IgG) was noted in 11.2% (31/277) of participants, whereas there was evidence of past infection in 75.5% (209/277) of participants (indirect IgG minus recent infections). The PRNT assay showed that the detected antibodies were indeed specific to DENV. The multivariate analysis showed that the older age group was significantly associated with past DENV infections. Seropositivity increased with age; 48.5% in the age group of <25 years to more than 85% in age group of >45 years (P 

    Matched MeSH terms: Dengue/blood; Dengue/immunology*; Dengue/epidemiology*; Dengue/transmission; Dengue Virus/immunology*; Dengue Virus/isolation & purification
  5. Thiruchelvam L, Dass SC, Asirvadam VS, Daud H, Gill BS
    Sci Rep, 2021 Mar 12;11(1):5873.
    PMID: 33712664 DOI: 10.1038/s41598-021-84176-y
    The state of Selangor, in Malaysia consist of urban and peri-urban centres with good transportation system, and suitable temperature levels with high precipitations and humidity which make the state ideal for high number of dengue cases, annually. This study investigates if districts within the Selangor state do influence each other in determining pattern of dengue cases. Study compares two different models; the Autoregressive Integrated Moving Average (ARIMA) and Ensemble ARIMA models, using the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) measurement to gauge their performance tools. ARIMA model is developed using the epidemiological data of dengue cases, whereas ensemble ARIMA incorporates the neighbouring regions' dengue models as the exogenous variable (X), into traditional ARIMA model. Ensemble ARIMA models have better model fit compared to the basic ARIMA models by incorporating neighbuoring effects of seven districts which made of state of Selangor. The AIC and BIC values of ensemble ARIMA models to be smaller compared to traditional ARIMA counterpart models. Thus, study concludes that pattern of dengue cases for a district is subject to spatial effects of its neighbouring districts and number of dengue cases in the surrounding areas.
    Matched MeSH terms: Dengue/epidemiology*
  6. Parkash O, Shueb RH
    Viruses, 2015 Oct 19;7(10):5410-27.
    PMID: 26492265 DOI: 10.3390/v7102877
    Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed.
    Matched MeSH terms: Dengue/diagnosis*
  7. Thapa B, Pandey A, Gautum S, Kc S, Chhetri PD, Pokhrel E, et al.
    J Nepal Health Res Counc, 2023 Jul 20;20(4):859-867.
    PMID: 37489668 DOI: 10.33314/jnhrc.v20i4.4172
    BACKGROUND: Dengue is a mosquito-borne viral disease with a wide spectrum of presentations ranging from subclinical disease to severe dengue. Dengue is endemic to the Terai of Nepal. Interestingly, an increasing incidence has been reported from hilly areas like Kathmandu valley. This study explored the clinicopathological profile of dengue infection.

    METHODS: A total of 84 serologically confirmed dengue cases from September to November 2019 at KIST Medical College were recruited in a cross-sectional study after obtaining ethical approval. Dengue was categorized as dengue without warning signs, dengue with warning signs, and severe dengue. Clinicopathological information was recorded in the proforma by reviewing patients' records. A descriptive statistical tool and chi-square test were carried out.

    RESULTS: Out of 84 patients, 76% (64) were dengue without warning signs, 21.4% (18) were dengue with warning signs and 2.4% (2) were severe dengue. About 97.6% (82) presented with fever. During the course of illness, anemia was identified in 38.1% (32), thrombocytopenia in 65.5% (55), hemoconcentration in 6% (5), and leucopenia in 82.1% (69). Similarly, elevated aspartate transaminase and alanine transaminase (ALT) was observed in 67.7% (42) and 53.2% (33) respectively. The severity of dengue on presentation to hospital was significantly associated with thrombocytopenia, leucopenia, and elevated ALT. Similarly, the severity during course of illness in hospital was significantly associated with hemoconcentration, thrombocytopenia, leucopenia, and elevated ALT.

    CONCLUSIONS: Most common presentation of dengue infection was fever. The most common laboratory abnormalities were leucopenia, thrombocytopenia, hemoconcentration, anemia, and elevated liver enzymes. Awareness of these clinical and laboratory parameters is important for the prompt diagnosis, severity estimation, and overall management of dengue infection.

    Matched MeSH terms: Severe Dengue*
  8. Norazharuddin H, Lai NS
    Malays J Med Sci, 2018 Sep;25(5):6-15.
    PMID: 30914859 DOI: 10.21315/mjms2018.25.5.2
    Dengue is a neglected disease caused by the infection of dengue virus which is transmitted by Aedes mosquitoes and to some, it could be fatal. Regardless of the enormous work devoted to research for the treatment of dengue, to this day there is no cure, and treatment is solely limited to supportive care by treating the symptoms. The inhibition of the viral RNA non-structural enzymes has been the most popular approach amongst the strategies applied to the search and development of dengue antivirals. This review is a compact digest of what is already known of the roles and the prospects of the dengue virus non-structural proteins NS1, NS2BNS3, NS4A, NS4B and NS5 as the targets for antiviral studies including the recent progress that has been published regarding their roles.
    Matched MeSH terms: Dengue; Dengue Virus
  9. Lee HL, Phong TV, Rohani A
    PMID: 23413698
    This study was conducted to determine the inhibitory effects of ribavirin and hydroxyurea on dengue virus replication in Aedes aegypti mosquitoes. Female Ae. aegypti mosquitoes were infected with dengue-2 virus and fed ribavirin at a dose of 0.3 mg/ml and/or hydroxyurea at a dose of 6 mg/ml via artificial membrane feeding technique. The virus in infected mosquitoes was isolated using C6/36 cell culture. Peroxidase-antiperoxidase (PAP) staining was used to detect dengue-infected C6/36 cells and to quantify the level of infection by determining the presence of infected cells. In mosquitoes treated with ribavirin alone, hydroxyurea alone or both drugs in combination had reductions in dengue infection rates of 87.72, 89.47 and 95.61%, respectively. The mortalities of female Ae. aegypti mosquitoes fed with these drugs were significantly higher than the control. Ribavirin also had an inhibitory effect on the fecundity of female Ae. aegypti mosquitoes.
    Matched MeSH terms: Dengue/prevention & control*; Dengue/transmission; Dengue/virology; Dengue Virus/drug effects*; Dengue Virus/isolation & purification; Dengue Virus/physiology
  10. Cardosa MJ
    PMID: 3217825
    Matched MeSH terms: Dengue/epidemiology*
  11. Rohani A, Zamree I, Joseph RT, Lee HL
    PMID: 19058573
    A study was conducted to examine the persistency of transovarial dengue virus type 2 (DEN-2) in a Selangor strain of Aedes aegypti mosquitoes. Two hundred 4-5 day old female mosquitoes were fed with blood containing dengue virus. The infected mosquitoes were reared to the 7th generation; each generation was screened for the virus using immunological staining methods. The virus was detectable until the 5th generation but absent in the 6th and the 7th generations. Therefore, dengue virus type 2 can be transmitted transovarially in Aedes aegypti mosquitoes until the fifth generation under laboratory conditions.
    Matched MeSH terms: Dengue Virus/isolation & purification*
  12. Yap HH
    PMID: 1226538
    An ovitrap survey was carried out in April and May of 1975 at twenty-one locations scattered throughout Penang Island excluding the City of Georgetown. The results showed the ubiquitous presence of Ae. albopictus. Ae. aegypti was recorded only in Tanjung Tokong Lama, an area adjacent to the City of Georgetown. In the survey, Ae. albopictus females were found to prefer the outdoor ovitraps than indoor ones. The effectiveness of ovitrap in Aedes survey was discussed.
    Matched MeSH terms: Dengue/transmission
  13. Chan SY, Kautner IM, Lam SK
    J Virol Methods, 1994 Oct;49(3):315-22.
    PMID: 7868649
    The potential of RT-PCR to rapidly diagnose dengue infections from both acute and convalescent phase patients' sera was evaluated. The RNA extraction method involved binding of the viral RNA to silica particles in the presence of high concentration of guanidine thiocyanate. The protocol that was established was sensitive enough to detect 40 plaque forming units per 100 microliter of serum and results could be obtained within one day. Results from this study indicate that clinical samples should be collected in the early acute phase of illness when anti-dengue antibodies were undetectable or of low titres to ensure a more reliable diagnosis.
    Matched MeSH terms: Dengue/diagnosis*; Dengue/immunology*; Dengue/virology; Dengue Virus/genetics; Dengue Virus/immunology; Dengue Virus/isolation & purification
  14. Ab Rahman SS, Nik Mazian A, Samad SZ
    Trop Med Int Health, 2023 Nov;28(11):864-868.
    PMID: 37778744 DOI: 10.1111/tmi.13936
    Dengue is endemic in over 100 countries worldwide, predominantly in the subtropical and tropical regions and the incidence has been increasing globally. Patients with severe dengue may develop massive bleeding, disseminated intravascular coagulopathy and multi-organ failure. Bleeding may occur in various body cavities and muscles; however, bleeding in the retroperitoneal space is uncommon. We report a case of a 37-year-old gentleman who presented with a 4-day history of fever associated with chills and rigours. On Day 6 of illness, he complained of left lumbar and left iliac fossa pain which was aggravated by movement. A computed tomography angiography scan of the abdomen showed the presence of a retroperitoneal haematoma, left iliopsoas and quadratus lumbarum intramuscular haematoma with active bleeding and left abdominal wall muscles haematoma. His condition gradually improved after multiple blood transfusions and he gained full recovery. Spontaneous retroperitoneal haematoma is an uncommon complication of severe dengue infection. Early diagnosis based on high index of clinical suspicion using appropriate imaging will aid in prompt management of these cases and may prevent deaths.
    Matched MeSH terms: Severe Dengue*
  15. Ngwe Tun MM, Muthugala R, Nabeshima T, Rajamanthri L, Jayawardana D, Attanayake S, et al.
    J Clin Virol, 2020 04;125:104304.
    PMID: 32145478 DOI: 10.1016/j.jcv.2020.104304
    BACKGROUND: Sri Lanka experienced its largest dengue outbreak in 2017 with more than 185,000 dengue cases including at least 250 fatalities.

    OBJECTIVES: Our study aimed to characterize the clinical, immunological and virological features of confirmed dengue patients in Sri Lanka during the outbreak in 2017 when unusual manifestations of severe dengue were observed.

    STUDY DESIGN: Sera from 295 patients who were admitted to Teaching Hospital Kandy, Kandy, Sri Lanka between March 2017- January 2018 were subjected to NS1 antigen, IgM and IgG ELISAs, virus isolation, conventional and real time RT-PCR and next generation sequencing.

    RESULTS: Primary and secondary infections were detected in 48.5 % and 51.5 % of the study population, respectively. Two hundred twenty five DENV strains were isolated (219 DENV-2, one DENV-3, two DENV-4, two mixed infections of DENV-2 and -3 and one mixed infection of DENV-2 and -4). Unusual and severe manifestations such as encephalitis, encephalopathy, liver failure, kidney failure, myocarditis, Guillain-Barré syndrome and multi-organ failure were noted in 44 dengue patients with 11 deaths. The viraemia levels in patients with primary infection and unusual manifestations were significantly higher compared to those in patients with secondary infection. A new clade of DENV-2 Cosmopolitan genotype strains was observed with the strains closely related to those from China, Malaysia, Indonesia, Singapore and Taiwan.

    CONCLUSIONS: The new clade of DENV-2 cosmopolitan genotype observed in Sri Lanka in 2017 caused an unprecedented, severe dengue outbreak. The emergence of DENV-3 and DENV-4 in the 2017 outbreak might cause future outbreaks in Sri Lanka.

    Matched MeSH terms: Dengue/complications*; Dengue/mortality; Dengue/epidemiology*; Dengue Virus/classification; Dengue Virus/genetics*; Dengue Virus/pathogenicity; Severe Dengue/mortality; Severe Dengue/epidemiology*
  16. Mallhi TH, Khan AH, Sarriff A, Adnan AS, Khan YH, Jummaat F
    Postgrad Med J, 2016 Feb;92(1084):78-86.
    PMID: 26729887 DOI: 10.1136/postgradmedj-2015-133582
    Several criteria have been used to stratify acute kidney injury (AKI) in dengue infection and have resulted in variations in its incidence as well as clinic-laboratory characteristics. The current study was aimed to compare three commonly used criteria of AKI among patients with dengue.
    Matched MeSH terms: Dengue
  17. Ling CY, Gruebner O, Krämer A, Lakes T
    Geospat Health, 2014 Nov;9(1):131-40.
    PMID: 25545931
    Spatio-temporal patterns of dengue risk in Malaysia were studied both at the address and the sub-district level in the province of Selangor and the Federal Territory of Kuala Lumpur. We geocoded laboratory-confirmed dengue cases from the years 2008 to 2010 at the address level and further aggregated the cases in proportion to the population at risk at the sub-district level. Kulldorff's spatial scan statistic was applied for the investigation that identified changing spatial patterns of dengue cases at both levels. At the address level, spatio-temporal clusters of dengue cases were concentrated at the central and south-eastern part of the study area in the early part of the years studied. Analyses at the sub-district level revealed a consistent spatial clustering of a high number of cases proportional to the population at risk. Linking both levels assisted in the identification of differences and confirmed the presence of areas at high risk for dengue infection. Our results suggest that the observed dengue cases had both a spatial and a temporal epidemiological component, which needs to be acknowledged and addressed to develop efficient control measures, including spatially explicit vector control. Our findings highlight the importance of detailed geographical analysis of disease cases in heterogeneous environments with a focus on clustered populations at different spatial and temporal scales. We conclude that bringing together information on the spatio-temporal distribution of dengue cases with a deeper insight of linkages between dengue risk, climate factors and land use constitutes an important step towards the development of an effective risk management strategy.
    Matched MeSH terms: Dengue/etiology; Dengue/epidemiology*; Dengue/prevention & control
  18. Ang LW, Cutter J, James L, Goh KT
    Epidemiol Infect, 2015 Jun;143(8):1585-93.
    PMID: 25245094 DOI: 10.1017/S0950268814002507
    To assess the impact of past dengue epidemics in Singapore, we undertook a national seroepidemiological study to determine the prevalence of past dengue virus (DENV) infection in the adult population in 2010 and make comparisons with the seroprevalence in 2004. The study involved residual sera from 3293 adults aged 18-79 years who participated in a national health survey in 2010. The overall prevalence of anti-DENV IgG antibodies was 56·8% (95% confidence interval 55·1-58·5) in 2010. The seroprevalence increased significantly with age. Males had significantly higher seroprevalence than females (61·5% vs. 53·2%). Among the three major ethnic groups, Malays had the lowest seroprevalence (50·2%) compared to Chinese (57·0%) and Indians (62·0%). The age-standardized seroprevalence in adults was significantly lower in 2010 (54·4%) compared to 2004 (63·1%). Older age, male gender, Indian ethnicity, permanent residency and being home-bound were independent risk factors significantly associated with seropositivity. About 43% of the Singapore adult resident population remain susceptible to DENV infection as a result of the successful implementation of a comprehensive nationwide Aedes surveillance and control programme since the 1970s. Vector suppression and concerted efforts of all stakeholders in the community remain the key strategy in the prevention and control of dengue.
    Matched MeSH terms: Dengue/ethnology; Dengue/immunology; Dengue/epidemiology*
  19. Yeo AS, Azhar NA, Yeow W, Talbot CC, Khan MA, Shankar EM, et al.
    PLoS One, 2014;9(4):e92240.
    PMID: 24727912 DOI: 10.1371/journal.pone.0092240
    Dengue represents one of the most serious life-threatening vector-borne infectious diseases that afflicts approximately 50 million people across the globe annually. Whilst symptomatic infections are frequently reported, asymptomatic dengue remains largely unnoticed. Therefore, we sought to investigate the immune correlates conferring protection to individuals that remain clinically asymptomatic.
    Matched MeSH terms: Dengue/virology*; Dengue Virus/pathogenicity*
  20. Wong WR, Krupin O, Sekaran SD, Mahamd Adikan FR, Berini P
    Anal Chem, 2014 Feb 4;86(3):1735-43.
    PMID: 24410440 DOI: 10.1021/ac403539k
    We present a compact, cost-effective, label-free, real-time biosensor based on long-range surface plasmon polariton (LRSPP) gold (Au) waveguides for the detection of dengue-specific immunoglobulin M (IgM) antibody, and we demonstrate detection in actual patient blood plasma samples. Two surface functionalization approaches are proposed and demonstrated: a dengue virus serotype 2 (DENV-2) functionalized surface to capture dengue-specific IgM antibody in blood plasma and the reverse, a blood plasma functionalized surface to capture DENV-2. The results obtained via these two surface functionalization approaches are comparable to, or of greater quality, than those collected by conventional IgM antibody capture enzyme linked immunosorbent assay (MAC-ELISA). Our second functionalization approach was found to minimize nonspecific binding, thus improving the sensitivity and accuracy of the test. We also demonstrate reuse of the biosensors by regenerating the sensing surface down to the virus (or antibody) level or down to the bare Au.
    Matched MeSH terms: Dengue/blood*; Dengue Virus/physiology*
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