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Dengue virus: epidemiology, biology, and disease aetiology
Canadian Journal of Microbiology
Dengue is a vector-borne viral disease caused by the flavivirus dengue virus (DENV). Approximately 400 million cases and 22 000 deaths occur due to dengue worldwide each year. It has been reported in more than 100 countries in tropical and subtropical regions. A positive-stranded enveloped RNA virus (DENV) is principally transmitted by Aedes mosquitoes. It has four antigenically distinct serotypes, DENV-1 to DENV-4, with different genotypes and three structural proteins and seven non-structural proteins. Clinical symptoms of dengue range from mild fever to severe dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), with thrombocytopenia, leucopenia, and increased vascular permeability. Although primary infection causes activation of immune responses against DENV serotypes, the severity of the disease is enhanced via heterotypic infection by various serotypes as well as antibody-dependent enhancement (ADE). The first licensed DENV vaccine was tetravalent CYD Denvaxia, but i...
A molecular evaluation of dengue virus pathogenesis and its latest vaccine strategies
Molecular biology …, 2011
More than one third of the world's population living in tropical and subtropical areas of the world is at risk of dengue infections and as many as 100 million people are yearly infected. This disease has reemerged during the past 20 years in the form of an epidemic. Dengue is caused by one of four related serotypes of dengue virus and often leads to severe forms of the disease, resulting commonly from secondary infections. Dengue virus is a mosquito borne virus, belongs to the family Flaviviridae and consists of a single stranded positive sense RNA genome. Like other RNA viruses it escapes defense mechanisms and neutralization attempts by mutations, which make it more resistant and adaptable to its environment. Antiviral strategies and vaccine development is thus impaired and hence to date there is no licensed vaccine available for dengue virus. Here we discuss various efforts made towards the identification of potential vaccine targets for dengue as well as various strategies employed by research groups/pharmaceutical companies towards the development of a successful dengue vaccine.
Prevalence of dengue virus, their infection, diagnosis, and challenges
Journal of applied biology and biotechnology, 2022
Dengue is a mosquito-borne viral disease in tropical and subtropical countries worldwide. Dengue disease is caused by four structurally similar but serologically distinct dengue virus serotypes (DENV1~4) [1-3]. Humans are the only known hosts of DENVs and the dengue disease spectra range from undifferentiated fever to severe hemorrhagic fever. Although the vast majority of people infected with DENVs remain asymptomatic, dengue is preliminary characterized by typical dengue fever, and in severe cases, DENV infection may result dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) [4]. The severe dengue, DHF, and DSS include leakage of vascular fluids, hemorrhagic manifestation, and shock accompanied by thrombocytopenia and abundant complement activation [5], and under such conditions, the patients need immediate hospitalization. The RNA genome of DENVs encodes only 10 proteins: The capsid protein (C-protein), pre-membrane protein (prM-protein), envelope protein (E-protein), and seven non-structural proteins (NS-protein) [6].
Pathogenesis of Dengue virus in Host immune system and its genomic variation
European Journal of Biology
Dengue viruses are the most prevalent arthropod-borne viral diseases in humans, infecting 50-100 million people each year. Its serotypes are the most common causes of arboviral illness, putting half of the world's population at risk of infection. Because there is no vaccine or antiviral medicines, the only way to manage the disease is to reduce the Aedes mosquito vectors. DENV infection can be asymptomatic or cause a self-limiting, acute febrile illness with varying degrees of severity. High fever, headache, stomach discomfort, rash, myalgia, and arthralgia are the typical symptoms of dengue fever (DF). Thrombocytopenia, vascular leakage, and hypotension are symptoms of severe dengue, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Systemic shock characterizes DSS, which can be deadly. Dengue virus infection pathogenesis is linked to a complex interaction between virus, host genes, and host immune response. Major drivers of disease vulnerability include host fac...
Current Understanding of the Pathogenesis of Dengue Virus Infection
Current Microbiology
The pathogenesis of dengue virus infection is attributed to complex interplay between virus, host genes and host immune response. Host factors such as antibody-dependent enhancement (ADE), memory cross-reactive T cells, anti-DENV NS1 antibodies, autoimmunity as well as genetic factors are major determinants of disease susceptibility. NS1 protein and anti-DENV NS1 antibodies were believed to be responsible for pathogenesis of severe dengue. The cytokine response of cross-reactive CD4+ T cells might be altered by the sequential infection with different DENV serotypes, leading to further elevation of pro-inflammatory cytokines contributing a detrimental immune response. Fcγ receptor-mediated antibody-dependent enhancement (ADE) results in release of cytokines from immune cells leading to vascular endothelial cell dysfunction and increased vascular permeability. Genomic variation of dengue virus and subgenomic flavivirus RNA (sfRNA) suppressing host immune response are viral determinant...
A Brief scenario of Dengue virus
Dengue is one of the most emerging vector-borne viral diseases. Prevalence has enlarged 30-fold in the last 50 years with the increased geographic expansion to new countries. An estimated 50 million dengue infection occurs annually and approximately 2.5 billion live in dengue endemic countries where more than 21,000 deaths occur each year. Dengue is anticipated to rise due to factors as contemporary modification of climate, travel, globalization, trade, viral evolution, socioeconomics and settlement. Poor disease scrutiny, misdiagnosis, limited public knowledge, low levels of reporting have found it hard to establish the accurate impact of dengue internationally. Dengue disease with accessible statistics possibly underestimates the pathophysiological, economic, social and ecological problems. Target of numerous vaccines now in progress is to bring out defensive neutralizing antibody responses are going on through clinical evaluation. The need of balanced immune response against all four DENV serotypes with a single vaccine is the main challenges encountering by the developers. The mortality can be reduced with prompt case detection, appropriate clinical management, and reporting but a safe and effective vaccine is probably the only long-term solution. Hence there is a need to build up an efficient, low-cost and safe vaccine that can target all the four serotypes of dengue virus.
The Open Public Health Journal
Dengue is the second most dangerous vector-borne disease worldwide in terms of incidence and mortality rate [1]. Many nations are experiencing dengue outbreaks, including the Americas, Africa, the Middle East, Asia, and the Pacific Islands [2]. Dengue, also known as dengue fever (DF), is a viral disease that is carried and spread by female mosquitos, mostly Aedes aegypti and to a lesser extent, Aedes albopictus. The virus belongs to the Flaviviridae family and has four separate but closely related serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) [3]. Whilst there are four types of the dengue virus, it is still possible to be re-infected as the immune system only becomes immune to one serotype at a time.
Understanding the Dengue Viruses and Progress towards Their Control
BioMed Research International, 2013
Traditionally, the four dengue virus serotypes have been associated with fever, rash, and the more severe forms, haemorrhagic fever and shock syndrome. As our knowledge as well as understanding of these viruses increases, we now recognise not only that they are causing increasing numbers of human infections but also that they may cause neurological and other clinical complications, with sequelae or fatal consequences. In this review we attempt to highlight some of these features in the context of dengue virus pathogenesis. We also examine some of the efforts currently underway to control this “scourge” of the tropical and subtropical world.