Dengue virus: epidemiology, biology, and disease aetiology

Abstract

Dengue is a vector-borne viral disease, caused by the Flavivirus, Dengue virus (DENV). About 400 million cases and 22000 deaths occur due to dengue throughout the world each year. It is reported in more than 100 countries in the tropics 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 4, with different genotypes, having three structural proteins and seven non-structural proteins. Clinical symptoms of dengue range from mild fever to severe Dengue Haemorrhagic Fever (DHF) or Dengue Shock Syndrome (DSS), with thrombocytopenia, leucopenia, and increased vascular permeability. Though primary infection causes activation of immune responses against that DENV serotypes, the severity of the disease in enhanced via heterotypic infection by various serotypes and also by antibody dependent enhancement (ADE). The first licensed DENV vaccine was tetravalent CYD Denvaxia, but it was not approved in all countries. Lack of suitable animal model, proper mechanistic study in pathogenesis and ADE, are the main hindrances in vaccine development. This review summarizes the current knowledge on DENV epidemiology, biology, disease etiology in the context of prevention and protection from dengue virus disease.

Advances and gaps in SARS-CoV-2 infection models

“…ADE, on the other hand, is a phenomenon where preexisting vaccine or infection-induced antibodies enhance infection of FcγR expressing target cells, which results in increased disease. ADE is well documented to occur after secondary infections with dengue viruses belonging to different serotypes [ 39 ].…”

Dengue Fever in Italy: The “Eternal Return” of an Emerging Arboviral Disease

“…Dengue fever is a mosquito-borne tropical disease caused by a positive-sense, singlestranded RNA virus belonging to the family of Flaviviridae (dengue virus, DENV). DENV is subdivided in four distinct serotypes (DENV 1-4) that share a limited genetical identity (approximately 65-70% amino acid sequence similarity) [1][2][3]. A fifth serotype (DENV-5) was detected in Malaysia in 2007, but its significance remains unclear [3].…”

Dengue Virus Infection: A Tale of Viral Exploitations and Host Responses

“…Dengue Hemorrhagic Fever (DHF) is characterized by extreme vascular permeability leading vascular leakage. DHF may ultimately lead to Dengue Shock Syndrome (DSS), which is characterized by decreased peripheral perfusion leading to tissue damage and the failure of multiple organs [ 2 ]. The event of the “cytokine storm”, referring to heightened production of cytokines ( Figure 4 ), majorly, IL-1, IL-2, IL-10, CXCL-10, CCL-2, VEGF, TNF-α, IFN-α, and IFN-γ, is observed in both conditions of DHF and DSS, which is not evident in mild/intermediate DF [ 81 , 82 , 83 , 84 ].…”

“…Increased IL-10 levels may also contribute to plasma leakage [ 86 ]. Moreover, cytotoxic factors released upon the activation of CD4+ Th cells trigger the macrophages to produce reactive nitrogen species that consecutively encourage the Th2 responses, ultimately instigating permeability changes and plasma leakage [ 2 ]. Although the antibodies produced during the primary DENV infection are extremely serotype-specific, during infection with a heterologous serotype, low-avidity memory cells may crosslink with the antigen to elicit a cytokine storm and result in similar complications [ 87 ].…”

“…Weak mosquito control policies, afforestation, climate change, and global warming are few of the reasons for this increase. Severe Dengue virus infection causes tenderness and belly pain, vomiting at least thrice a day, epistaxis, hematemesis, melena, fatigue, and restlessness, which finally lead to hemorrhagic fever and organ failure [ 2 ]. Four different serotypes of the Dengue virus are found worldwide.…”