Detection of the Disease Severity‐Related Molecular Differences among New Thai Dengue‐2 Isolates in 1993, Based on Their Structural Proteins and Major Non‐Structural Protein NS1 Sequences

Thant, Kyaw-Zin; Morita, Kouichi; Igarashi, Akira

doi:10.1111/j.1348-0421.1996.tb03336.x

Cited by 19 publications

(15 citation statements)

References 65 publications

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“…These lengths were identical to those of most other strains sequenced previously (6,7,11,27,42,43). Phylogenetic trees produced with the maximum-parsimony and neighbor-joining methods produced very similar topologies, differing only within a few terminal groupings in the DEN-3 and DEN-4 groups.…”

Section: Resultssupporting

confidence: 49%

Evolutionary Relationships of Endemic/Epidemic and Sylvatic Dengue Viruses

Wang

et al. 2000

J Virol

360

298

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Endemic/epidemic dengue viruses (DEN) that are transmitted among humans by the mosquito vectors Aedes aegypti and Aedes albopictus are hypothesized to have evolved from sylvatic DEN strains that are transmitted among nonhuman primates in West Africa and Malaysia by other Aedes mosquitoes. We tested this hypothesis with phylogenetic studies using envelope protein gene sequences of both endemic/epidemic and sylvatic strains. The basal position of sylvatic lineages of DEN-1, -2, and -4 suggested that the endemic/epidemic lineages of these three DEN serotypes evolved independently from sylvatic progenitors. Time estimates for evolution of the endemic/epidemic forms ranged from 100 to 1,500 years ago, and the evolution of endemic/epidemic forms represents relatively recent events in the history of DEN evolution. Analysis of envelope protein amino acid changes predicted to have accompanied endemic/epidemic emergence suggested a role for domain III in adaptation to new mosquito and/or human hosts.Dengue viruses (DEN) (Flaviviridae: Flavivirus) are serious human pathogens that occur nearly throughout the tropics, with ca. 100 million cases annually (16). DEN comprise four serotypes (DEN-1 to DEN-4); although epidemiologically similar, they are genetically and antigenically distinct. Infection with one serotype leads to lifelong protection against homologous reinfection but only brief protection against heterologous challenge (21, 38).DEN cause dengue fever, a self-limited febrile illness lasting 2 to 10 days that has been known in the medical literature for over 200 years. Infrequent epidemics of dengue fever occurred in tropical areas until the 1950s. After War World II, this pattern of disease was disrupted by the emergence of dengue hemorrhagic fever and dengue shock syndrome, more severe diseases characterized by thrombocytopenia, hemorrhage, and excessive plasma leakage (16,28). Two principal hypotheses have been proposed to explain the hemorrhagic form of disease: (i) the immune enhancement theory maintains that hemorrhage occurs in secondary infections when DEN-specific antibodies and memory T cells resulting from primary infection with another serotype enhance the binding of virus-immunoglobulin G complexes to FcY receptors on monocytic cells, and (ii) certain phenotypes of DEN are more virulent than others. Recent phylogenetic studies suggest that an Asian genotype of DEN-2 recently introduced into the New World may be associated with increased risk for hemorrhagic fever and shock in the presence of heterologous antibody (32). DEN strains of reduced virulence have also been described; endemic transmission on the South Pacific islands of Tonga, involving vectors other than Aedes aegypti, may result in less severe disease because of the lesser selection for high viremia imposed by more susceptible vectors, like Aedes polynesiensis (13). Two distinct DEN transmission cycles occur: (i) endemic and epidemic DEN involving human hosts and transmission byA. aegypti, with Aedes albopictus and other Aedes mosquitoes serv...

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Section: Resultssupporting

confidence: 49%

Evolutionary Relationships of Endemic/Epidemic and Sylvatic Dengue Viruses

Wang

et al. 2000

J Virol

360

298

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“…10 -5 subs/site/year has been obtained [30]. In addition, the NS1 gene was included in this analysis, as this protein is also involved in determination of viral virulence on the basis of its significance for virus entry and assembly [31].…”

Section: Discussionmentioning

confidence: 99%

E/NS1 Modifications of Dengue 2 Virus after Serial Passages in Mammalian and/or Mosquito Cells

Chen

Chiou

2003

Intervirology

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Objective: Dengue viruses are routinely maintained in nature by transmission cycles involving the passage of virus between humans and Aedes mosquitoes. The number of dengue virus lineages has been increasing over time. The aim of this study was to identify the genetic diversity of dengue 2 virus serially transferred in mammalian and/or mosquito cells. Methods: The E/NS1 gene of dengue 2 virus variants derived from serial passages in Vero or C6/36 cells, or alternately in both cell systems, was amplified and sequenced in order to observe gene modification after serial passages. Results: Three nucleotides (two in E and one in NS1) or two amino acids (one each in E and NS1) changed in the virus that was continuously cultured in Vero cells for 20 passages, whereas four nucleotides (two each in E and NS1) or three amino acids (one in E and two in NS1) changed in the virus cultured for 30 passages. The genome of dengue 2 virus remained stable even when the virus was serially transferred in C6/36 cells for 30 generations. However, there was one amino acid substitution (E₄₆ I→V) resulting from a single nucleotide change in the E region of dengue 2 virus alternately transferred in C6/36 and Vero cells for either 20 or 30 passages. In addition, dengue 2 virus obtained from serially cultured Vero cells usually replicated better when it reinfected Vero cells, reflecting its high adaptation fitness to the host cell. Conclusions: It is concluded that genetic changes of dengue 2 virus are constrained in Vero (mammalian) cells, resulting in a variety of genome-related quasispecies populations. Some populations of the virus are subsequently selected by and genetically (at least in the E/NS1 portion of the viral genome) maintained in C6/36 (mosquito) cells during replicative competition.

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“…Reports based upon the epidemiological data advocate that particular serotypes appear to be more virulent than others with certain ethnic groups [101-106]. In addition, experimental results also suggest that certain genotypes within a serotype encode determinants for virulence, attenuation, and tissue tropism [107-111]. However, substantiation of the virulent strain hypothesis of dengue pathogenesis still awaits the availability of an adequate disease model for validation [112,113].…”

Section: Introductionmentioning

confidence: 99%

Role of cognitive parameters in dengue hemorrhagic fever and dengue shock syndrome

et al. 2013

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Dengue is becoming recognized as one of the most important vector-borne human diseases. It is predominant in tropical and subtropical zones but its geographical distribution is progressively expanding, making it an escalating global health problem of today. Dengue presents with spectrum of clinical manifestations, ranging from asymptomatic, undifferentiated mild fever, dengue fever (DF), to dengue hemorrhagic fever (DHF) with or without shock (DSS), a life-threatening illness characterized by plasma leakage due to increased vascular permeability. Currently, there are no antiviral modalities or vaccines available to treat and prevent dengue. Supportive care with close monitoring is the standard clinical practice. The mechanisms leading to DHF/DSS remains poorly understood. Multiple factors have been attributed to the pathological mechanism, but only a couple of these hypotheses are popular in scientific circles. The current discussion focuses on underappreciated factors, temperature, natural IgM, and endotoxin, which may be critical components playing roles in dengue pathogenesis.

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Detection of the Disease Severity‐Related Molecular Differences among New Thai Dengue‐2 Isolates in 1993, Based on Their Structural Proteins and Major Non‐Structural Protein NS1 Sequences

Cited by 19 publications

References 65 publications

Evolutionary Relationships of Endemic/Epidemic and Sylvatic Dengue Viruses

Evolutionary Relationships of Endemic/Epidemic and Sylvatic Dengue Viruses

E/NS1 Modifications of Dengue 2 Virus after Serial Passages in Mammalian and/or Mosquito Cells

Role of cognitive parameters in dengue hemorrhagic fever and dengue shock syndrome

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