Displaying publications 1 - 20 of 350 in total

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  1. [Laboratory diagnosis and molecular tracing of dengue bordline cases in Henan Province, 2017]
    Du YH, Li Y, Wang RL, Wang HF, Su J, Xu BL, et al.
    Zhonghua Yu Fang Yi Xue Za Zhi, 2018 Nov 06;52(11):1164-1167.
    PMID: 30419702 DOI: 10.3760/cma.j.issn.0253-9624.2018.11.013
    Objective: To confirm the laboratory diagnosis of dengue bordline cases reported in Henan Province and trace its origin from molecular level in 2017. Methods: The study samples were blood samples (3-5 ml), which came from 8 suspected cases of dengue fever reported in the 2017 direct reporting system of Henan provincial infectious disease monitoring network. Meanwhile, case investigation was conducted according to National dengue fever surveillance programme. Serum were separated from blood samples and tested for Dengue NS1 antigen, IgM & IgG antibodies, and dengue RNA. According to dengue diagnosis criteria, confirmed cases were identified by testing results. Samples carried dengue RNA performed for real-time PCR genotyping and amplification of E gene. Then, the amplicons were sequenced and homological and phylogenetic analyses were constructed. Results: 8 serum samples of suspected dengue cases were collected in Henan Province, 2017. Six of them were diagnosed as dengue confirmed cases. All the dengue confirmed cases belonged to outside imported cases, 5 of them were positive by dengue RNA testing. Genotyping results showed there were 1 DENV1 case, 2 DENV2 cases and 2 DENV3 cases. A DENV2 case and a DENV3 case of this study were traced its origin successfully. The sequence of Pakistan imported DENV2 case belongs to cosmopolitan genotype, which was the most consistent with Pakistan's DENV2 KJ010186 in 2013 (identity 99.0%). The sequence of Malaysia imported DENV3 case belongs to genotype I, which was the most consistent with Singapore's DENV3 KX224276 in 2014(identity 99.0%). Conclusion: The laboratory diagnosis and molecular traceability of dengue cases in Henan Province in 2017 confirmed that all cases were imported and did not cause local epidemics.
    Matched MeSH terms: Dengue Virus/genetics*; Dengue Virus/isolation & purification
  2. [Is the fight against dengue complicated with the emergence of a new viral serotype?]
    Valero N, Quiroz Y
    Invest Clin, 2014 Sep;55(3):203-5.
    PMID: 25272519
    Dengue is a viral acute febrile illness, currently considered one of the most important arbovirosis worldwide in terms of morbidity, mortality and economic impact. Various theories have been proposed to explain the pathogenesis of severe forms of dengue, involving among other factors, features related to the virus, such as the presence of more virulent strains and/or strains with increased replicative capacity. A crucial point at this time is the discovery of a new viral type, dengue 5, from nonhuman primates in Malaysia-Borneo, which could result in greater difficulties for control and vaccine production (currently in efficacy tests). Once the circulation of this viral type has been demonstrated in the human population, the high risk of infection will have extreme or controversial public health implications. Therefore, a worldwide program to combat dengue should include an urgent need to implement continuous vector elimination, community education and prevention and control of the disease. Only then, we will be aiming to reduce the morbidity and transmission risk of dengue, while new technological and effective alternatives come about.
    Matched MeSH terms: Dengue Virus/classification*
  3. [Identification and sequence analysis of E gene of Dengue virus type 2 strain isolated from patient serum in Shenzhen]
    Yang F, He JF, Xian HX, Zhang HL, He YQ, Yang H, et al.
    Zhonghua Yu Fang Yi Xue Za Zhi, 2009 Sep;43(9):798-802.
    PMID: 20137564
    To isolate and identify the pathogen of Dengue fever from Shenzhen city in 2005 - 2006, and to analyze the molecular characteristics of the isolated Dengue virus strain as well as to explore its possible origin.
    Matched MeSH terms: Dengue Virus/classification; Dengue Virus/genetics*; Dengue Virus/isolation & purification*
  4. [Hemorrhagic dengue fever after trip to Malaysia]
    Hafner C, Koellner K, Vogt T, Landthaler M, Szeimies RM
    Hautarzt, 2006 Aug;57(8):705-7.
    PMID: 16283129
    A 39-year-old patient developed a disseminated rash with scattered petechiae, fever, malaise and arthralgia after a trip to Malaysia. The patient displayed increasing dengue IgG titers and borderline dengue IgM titers. Dengue fever with a hemorrhagic course is a rare condition in adult patients. Patients who have previously had dengue fever and retained non-neutralizing heterotypic antibodies are more likely to develop this complication via the phenomenon of antibody-dependent enhancement.
    Matched MeSH terms: Dengue Virus/immunology
  5. [A possible fifth dengue virus serotype]
    da Silva Voorham JM
    Ned Tijdschr Geneeskd, 2014;158:A7946.
    PMID: 25227888
    Sylvatic dengue viruses are both evolutionarily and ecologically distinguishable from the human dengue virus (DENV). Sporadic episodes of sylvatic human infections in West Africa and Southeast Asia suggest that sylvatic DENV regularly come into contact with human beings. Following a study on the sylvatic transmission cycle in Malaysia in 2007, researchers announced that a new DENV serotype, DENV-5, had been discovered. Scientists are still sceptical about these new findings, and indicate that more data is necessary to determine whether this 'new' virus really is a different serotype or whether it is a variant of one of the four DENV serotypes already known. The good news is that this new variant has not yet established itself in the human transmission cycle. However, if it really is a new serotype this will have implications for the long-term control of dengue using vaccines currently under development.
    Matched MeSH terms: Dengue Virus/classification*; Dengue Virus/immunology
  6. Zinc accelerates dengue virus type 2-induced apoptosis in Vero cells
    Shafee N, AbuBakar S
    FEBS Lett., 2002 Jul 31;524(1-3):20-4.
    PMID: 12135735
    Dengue virus type 2 (DENV-2) infection induced apoptotic cellular DNA fragmentation in Vero cells within 8 days of infection. The addition of high concentrations of extracellular Zn(2+) but not Ca(2+), Mg(2+) or Mn(2+) to the cell culture medium hastened the detection of apoptosis to within 4 h after infection. No apoptotic cellular DNA fragmentation was detected in the cell culture treated with Zn(2+) alone or infected with heat- or ultraviolet light-inactivated DENV-2 in the presence of Zn(2+). These results suggest that (i) apoptosis is induced in African green monkey kidney cells infected with live DENV-2 and (ii) the addition of high extracellular Zn(2+) accelerates detection of apoptosis in the DENV-2-infected cells.
    Matched MeSH terms: Dengue Virus/physiology*
  7. Fulltext Wolbachia strain wAlbB maintains high density and dengue inhibition following introduction into a field population of Aedes aegypti
    Ahmad NA, Mancini MV, Ant TH, Martinez J, Kamarul GMR, Nazni WA, et al.
    Philos Trans R Soc Lond B Biol Sci, 2021 02 15;376(1818):20190809.
    PMID: 33357050 DOI: 10.1098/rstb.2019.0809
    Aedes aegypti mosquitoes carrying the wAlbB Wolbachia strain show a reduced capacity to transmit dengue virus. wAlbB has been introduced into wild Ae. aegypti populations in several field sites in Kuala Lumpur, Malaysia, where it has persisted at high frequency for more than 2 years and significantly reduced dengue incidence. Although these encouraging results indicate that wAlbB releases can be an effective dengue control strategy, the long-term success depends on wAlbB maintaining high population frequencies and virus transmission inhibition, and both could be compromised by Wolbachia-host coevolution in the field. Here, wAlbB-carrying Ae. aegypti collected from the field 20 months after the cessation of releases showed no reduction in Wolbachia density or tissue distribution changes compared to a wAlbB laboratory colony. The wAlbB strain continued to induce complete unidirectional cytoplasmic incompatibility, showed perfect maternal transmission under laboratory conditions, and retained its capacity to inhibit dengue. Additionally, a field-collected wAlbB line was challenged with Malaysian dengue patient blood, and showed significant blocking of virus dissemination to the salivary glands. These results indicate that wAlbB continues to inhibit currently circulating strains of dengue in field populations of Ae. aegypti, and provides additional support for the continued scale-up of Wolbachia wAlbB releases for dengue control. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'.
    Matched MeSH terms: Dengue Virus/physiology
  8. Fulltext Whole Genome Sequencing-Based Molecular Epidemiologic Analysis of Autochthonous Dengue Virus Type 1 Strains Circulating in Japan in 2014
    Tajima S, Nakayama E, Kotaki A, Moi ML, Ikeda M, Yagasaki K, et al.
    Jpn J Infect Dis, 2017 Jan 24;70(1):45-49.
    PMID: 27169954 DOI: 10.7883/yoken.JJID.2016.086
    Cases of autochthonous infections of dengue virus type 1 (DENV-1) were detected in Japan after a 70-year period devoid of dengue outbreaks. We previously showed that E gene sequences are identical in 11 of the 12 DENV-1 strains autochthonous to Japan. However, the E sequence represents only 14% of the DENV-1 genome. In the present study, we have sequenced the entire genome of 6 autochthonous DENV-1 strains that were isolated from patients during the 2014 outbreak. Sequencing of 5 Yoyogi group strains with identical E sequences and 1 Shizuoka strain with a different E sequence revealed that the first Yoyogi group strain differed from the Shizuoka strain by 18 amino acid residues. Furthermore, 2 Yoyogi group strains had different genomic sequences while the other 3 had identical genomes. Phylogenetic analyses indicated that the Hyogo strain, a Yoyogi group strain, was the first to diverge from the other 4 Yoyogi group strains. The E gene sequence of the Yoyogi group strains exhibits the highest homology to those of the strains isolated in Malaysia and Singapore between 2013 and 2014. The patient infected with the Hyogo strain visited Malaysia before the onset of dengue fever, suggesting that this was a case of dengue infection imported from Malaysia.
    Matched MeSH terms: Dengue Virus/classification*; Dengue Virus/genetics*; Dengue Virus/isolation & purification
  9. Fulltext War against dengue: we lack tools to win the war
    Lokman Hakim Sulaiman
    International e-Journal of Science, Medicine & Education, 2018;12(1):1-3.
    MyJurnal
    Dengue is the most rapidly increasing arthropodborne
    disease globally. The disease burden has increased
    exponentially, doubling almost every decade from the
    estimated 8.3 million cases in 2010 to about 58.4 million
    cases in 2013.1
    The number of countries reporting
    dengue has also increased. Before 1970, less than 9
    countries reported dengue but now it has been reported
    in more than 100 countries worldwide. It is transmitted
    by two species of Aedes mosquito, Aedes aegypti and Ae.
    albopictus. (Copied from article).
    Matched MeSH terms: Dengue Virus
  10. Fulltext Virus-specific read-through codon preference affects infectivity of chimeric cucumber green mottle mosaic viruses displaying a dengue virus epitope
    Teoh PG, Ooi AS, AbuBakar S, Othman RY
    J Biomed Biotechnol, 2009;2009:781712.
    PMID: 19325913 DOI: 10.1155/2009/781712
    A Cucumber green mottle mosaic virus (CGMMV) was used to present a truncated dengue virus type 2 envelope (E) protein binding region from amino acids 379 to 423 (EB4). The EB4 gene was inserted at the terminal end of the CGMMV coat protein (CP) open reading frame (ORF). Read-through sequences of TMV or CGMMV, CAA-UAG-CAA-UUA, or AAA-UAG-CAA-UUA were, respectively, inserted in between the CP and the EB4 genes. The chimeric clones, pRT, pRG, and pCG+FSRTRE, were transcribed into full-length capped recombinant CGMMV transcripts. Only constructs with the wild-type CGMMV read-through sequence yielded infectious viruses following infection of host plant, muskmelon (Cucumis melo) leaves. The ratio of modified to unmodified CP for the read-through expression clone developed was also found to be approximately 1:1, higher than what has been previously reported. It was also observed that infectivity was not affected by differences in pI between the chimera and its wild counterpart. Analysis of recombinant viruses after 21-days-postinculation (dpi) revealed that deletions occurred resulting in partial reversions of the viral population to near wild type and suggesting that this would be the limiting harvest period for obtaining true to type recombinants with this construct.
    Matched MeSH terms: Dengue Virus/genetics*; Dengue Virus/immunology*
  11. Viability of dengue virus in culture stocks is efficiently preserved by storage in diluted forms
    Suppiah J, Nadaraju S, Hamzah S, Chee HY
    Trop Biomed, 2020 Jun 01;37(2):282-287.
    PMID: 33612798
    Storage of dengue virus (DENV) culture stocks in -80°C is a common laboratory practice to maintain the viability of the virus for long-term usage. However, the efficiency of this method could still be hindered by multiple factors. In our laboratory, we observed a constant and substantial deterioration in the titer of DENV in Vero culture supernatant stored in -80°C. Such incident had badly hampered the laboratory work and prompted an investigation to determine the cause. DENV isolates representing all four serotypes were propagated and the culture supernatants were harvested and stored in aliquots of original stock and 10 fold dilutions (10-1 -10-4). DENV titer in these stocks was determined prior to storage and reassessed on the third and sixth month of storage by focus forming unit assay (FFUA). The result demonstrated a constant preservation of titer ranging from 104 ffu/ml to 105 ffu/ml in the diluted DENV virus culture stocks of 10-1, and 10-2 of DENV1-4, a minor reduction of titer from 103 ffu/ml to 102 ffu/ml at dilution 10-3 for DENV4 only and complete deterioration in undiluted culture stock and lower dilution (10-4) within 6 months of storage in -80°C for all serotypes. It is recommended that propagated DENV in Vero cells are stored in 10 fold dilutions as compared to the original form to preserve the titer for long-term usage.
    Matched MeSH terms: Dengue Virus/physiology*
  12. Vector competence of Malaysian Aedes albopictus with and without Wolbachia to four dengue virus serotypes
    Joanne S, Vythilingam I, Teoh BT, Leong CS, Tan KK, Wong ML, et al.
    Trop Med Int Health, 2017 09;22(9):1154-1165.
    PMID: 28653334 DOI: 10.1111/tmi.12918
    OBJECTIVE: To determine the susceptibility status of Aedes albopictus with and without Wolbachia to the four dengue virus serotypes.

    METHODS: Two newly colonised colonies of Ae. albopictus from the wild were used for the study. One colony was naturally infected with Wolbachia while in the other Wolbachia was removed by tetracycline treatment. Both colonies were orally infected with dengue virus-infected fresh blood meal. Dengue virus load was measured using quantitative RT-PCR at four-time intervals in the salivary glands, midguts and ovaries.

    RESULTS: Wolbachia did not significantly affect Malaysian Ae. albopictus dengue infection or the dissemination rate for all four dengue virus serotypes. Malaysian Ae. albopictus had the highest replication kinetics for DENV-1 and the highest salivary gland and midgut infection rate for DENV-4.

    CONCLUSION: Wolbachia, which naturally exists in Malaysian Ae. albopictus, does not significantly affect dengue virus replication. Malaysian Ae. albopictus is susceptible to dengue virus infections and capable of transmitting dengue virus, especially DENV-1 and DENV-4. Removal of Wolbachia from Malaysian Ae. albopictus would not reduce their susceptibility status.

    Matched MeSH terms: Dengue Virus/classification; Dengue Virus/pathogenicity*
  13. Fulltext Use of dengue blot in dengue diagnosis: the Malaysian experience
    Fang R, Sinniah M, Kuen LS
    Malays J Pathol, 1992 Dec;14(2):117-20.
    PMID: 1304624
    Dengue fever/Dengue haemorrhagic fever (DF/DHF) has been a public health problem in Malaysia with an endemic level of about 7 per 100,000 population per year. In 1990, Malaysia experienced its most severe outbreak of DF/DHF with a record total of 5,590 cases referred to the Division of Virology, Institute for Medical Research (IMR). Of these, 1,880 were confirmed serologically to be DF/DHF. The conventional serological procedure, the Haemagglutination Inhibition (HI) test, for the diagnosis of DF/DHF is cumbersome and causes delay in diagnosis. Another problem associated with the HI test has been that it has often been difficult to obtain a second convalescent serum sample for an accurate diagnosis. This has raised an urgent need to establish a "rapid" test for diagnosis of DF/DHF. As such the authors recently carried out an evaluation of a newly available commercial rapid test, namely, the Dengue Blot Assay (Diagnostic Biotechnology Singapore Pte Ltd). The test is intended for use in laboratory confirmation of dengue virus infection. The evaluation was to determine if the test could be utilised as a routine laboratory test and to establish its sensitivity and specificity. Over 400 samples were tested against the Dengue Blot Assay. Results were checked against an in-house Dengue IgM ELISA and HI assay. Preliminary results indicate that the sensitivity and specificity of the Dengue Blot is satisfactory. Our results also indicate that the Dengue Blot has a useful role to play in a routine laboratory especially since it provides rapid results on single serum samples thereby reducing the workload in a busy diagnostic laboratory.
    Matched MeSH terms: Dengue Virus/isolation & purification*
  14. Fulltext Use of dengue NS1 antigen for early diagnosis of dengue virus infection
    Kassim FM, Izati MN, TgRogayah TA, Apandi YM, Saat Z
    Southeast Asian J. Trop. Med. Public Health, 2011 May;42(3):562-9.
    PMID: 21706934
    Accurate and timely diagnosis of dengue virus is important for early detection of dengue virus infection. In this study, the usefulness of the dengue NS1 antigen test was evaluated as a routine, rapid diagnostic test for dengue virus infection. A total of 208 sera from patients suspected of having dengue virus infection were collected and tested for dengue antibody, dengue genome and dengue NS1 antigen. Dengue antibody test, dengue PCR test and dengue antigen test were able to detect dengue virus infection from Days 1 to 8 in 72.8, 52.8 and 44.0% of samples, respectively. Of the 208 sera tested, 69.2% (144/208) of the acute sera were positive for dengue virus infection based on IgM antibody, IgG antibody, NS1 antigen and PCR tests. Thirty-two point two percent of the samples (67/208) were found positive for dengue NS1 antigen, 38.5% (80/208) were PCR positive, 40.9% (85/208) were IgM positive and 36.1% (75/208) were IgG positive for dengue virus. The results reveal the detection rate of dengue virus infection was similar for PCR and dengue antibody (65.9%) and for NS1 antigen and dengue antibody (62.0%) combinations. Therefore, the dengue NS1 antigen test can be used to complement the current antibody test used in peripheral laboratories. Thus, the combination of the NS1 antigen and antibody tests could increase the diagnostic efficiency for early diagnosis of dengue infection.
    Matched MeSH terms: Dengue Virus/genetics; Dengue Virus/immunology*; Dengue Virus/isolation & purification
  15. Update on temporal and spatial abundance of dengue vectors in Penang, Malaysia
    Saifur RG, Hassan AA, Dieng H, Ahmad H, Salmah MR, Satho T, et al.
    J Am Mosq Control Assoc, 2012 Jun;28(2):84-92.
    PMID: 22894118
    It is important to obtain frequent measurements of the abundance, distribution, and seasonality of mosquito vectors to determine the risk of disease transmission. The number of cases of dengue infection has increased in recent years on Penang Island, Malaysia, with recurring epidemics. However, ongoing control attempts are being critically hampered by the lack of up-to-date information regarding the vectors. To overcome this problem, we examined the current situation and distribution of dengue vectors on the island. Residences throughout the urban, suburban, and rural areas were inspected through wet and dry seasons between February 2009 and February 2010. Two vectors were encountered in the survey, with Aedes aegypti present in especially high numbers mostly in urban areas. Similar observations were noted for Ae. albopictus in rural areas. The former species was more abundant in outdoor containers, while the latter showed almost equivalent abundance both outdoors and indoors. The dengue virus was active in both urban and rural areas, and the number of cases of infection was higher in areas where Ae. aegypti was predominant. The abundance of immature Ae. albopictus was positively correlated with rainfall (r2 = 0.461; P < 0.05), but this was not the case for Ae. aegypti. For both species, the size of immature populations tended to increase with increasing intensity of rain, but heavy rains resulted in population loss. In addition to updating data regarding the larval habitats and locations (outdoors and indoors), this study highlighted the importance of spatial vector control stratification, which has the potential to reduce costs in control programs.
    Matched MeSH terms: Dengue Virus/physiology
  16. Unusual, neurological and severe dengue manifestations during the outbreak in Sri Lanka, 2017
    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 Virus/classification; Dengue Virus/genetics*; Dengue Virus/pathogenicity
  17. Unusual co-infection of severe malaria by Plasmodium vivax and dengue virus in Mexico
    Queb-Pech NM, Núñez-Oreza LA, Estrada-Méndez A, Tamay-Segovia P, Collí-Heredia JP, Blum-Domínguez SC
    Trop Biomed, 2022 Dec 01;39(4):575-578.
    PMID: 36602218 DOI: 10.47665/tb.39.4.014
    Malaria and dengue fever are among the most common mosquito-borne diseases worldwide; however, reports of coinfection are rare. We present a case of severe malaria and dengue coinfection in a 16-yearold female patient presenting with fever, thrombocytopenia, pleural effusion, myopericarditis, and acute respiratory distress syndrome. Dengue infection was confirmed by the presence of immunoglobin M antibodies and nonstructural protein 1, while malaria was confirmed by the presence of Plasmodium vivax in thick and thin blood smears. This is the first report of a dengue/malaria coinfection in Mexico.
    Matched MeSH terms: Dengue Virus*
  18. Ultrastructural changes of cell morphology and viral morphogenesis of two ecotypes of dengue virus infection in human monocytic U-937 cell
    Fish-Low CY, Abu Bakar S, Othman F, Chee HY
    Trop Biomed, 2018 Dec 01;35(4):1154-1159.
    PMID: 33601863
    Dengue virus (DENV) is maintained and circulated in both sylvatic/enzootic and endemic/human cycles and spill over infection of sylvatic DENV into human populations has been reported. Extensive deforestation and increase human activities in forest may increase the risk of human exposure to sylvatic dengue infection and this may become a threat to human. Present study investigated the changes in cell morphology and viral morphogenesis upon infection with sylvatic and endemic ecotypes in human monocytic U-937 cells using transmission electron microscopy. Autophagy, a process that is either pro-viral or anti-viral, was observed in U-937 cells of both infections, however only the replication of endemic DENV was evidenced. An insight into the infection responses of sylvatic progenitors of DENV in susceptible host cells may provide better understanding on dengue emergence in human populations.
    Matched MeSH terms: Dengue Virus
  19. Ultrastructural aspects of sylvatic dengue virus infection in Vero cell
    Fish-Low CY, Abubakar S, Othman F, Chee HY
    Malays J Pathol, 2019 Apr;41(1):41-46.
    PMID: 31025636
    INTRODUCTION: Dengue virus (DENV), the causative agent of dengue disease exists in sylvatic and endemic ecotypes. The cell morphological changes and viral morphogenesis of two dengue ecotypes were examined at the ultrastructural level to identify potential similarities and differences in the surrogate model of enzootic host.

    MATERIALS AND METHODS: Vero cells were inoculated with virus at a multiplicity of infection (MOI) of 0.1. Cell cultures were harvested over a time course and processed for transmission electron microscopic imaging.

    RESULTS: The filopodia protrusions on cell periphery preceded virus entry. Additionally, sylvatic DENV infection was found spreading slower than the endemic DENV. Morphogenesis of both dengue ecotypes was alike but at different level of efficiency in the permissive cells.

    CONCLUSIONS: This is the first ultrastructural study on sylvatic DENV and this comparative study revealed the similarities and differences of cellular responses and morphogenesis of two dengue ecotypes in vitro. The study revealed the weaker infectivity of sylvatic DENV in the surrogate model of enzootic host, which supposed to support better replication of enzootic DENV than endemic DENV.

    Matched MeSH terms: Dengue Virus
  20. Type-3 dengue viruses responsible for the dengue epidemic in Malaysia during 1993-1994
    Kobayashi N, Thayan R, Sugimoto C, Oda K, Saat Z, Vijayamalar B, et al.
    Am J Trop Med Hyg, 1999 Jun;60(6):904-9.
    PMID: 10403318
    To characterize the dengue epidemic that recently occurred in Malaysia, we sequenced cDNAs from nine 1993-1994 dengue virus type-3 (DEN-3) isolates in Malaysia (DEN-3 was the most common type in Malaysia during this period). Nucleic acid sequences (720 nucleotides in length) from the nine isolates, encompassing the precursor of membrane protein (preM) and membrane (M) protein genes and part of the envelope (E) protein gene were aligned with various reference DEN-3 sequences to generate a neighbor-joining phylogenetic tree. According to the constructed tree, the nine Malaysian isolates were grouped into subtype II, which comprises Thai isolates from 1962 to 1987. Five earlier DEN-3 virus Malaysian isolates from 1974 to 1981 belonged to subtype I. The present data indicate that the recent dengue epidemic in Malaysia was due to the introduction of DEN-3 viruses previously endemic to Thailand.
    Matched MeSH terms: Dengue Virus/classification*; Dengue Virus/genetics; Dengue Virus/chemistry
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