Dengue virus type 3 (DENV-3) is one of the four serotypes of dengue virus, an enveloped, positive-sense single-stranded RNA virus in the genus Flavivirus that causes dengue fever and severe dengue. It is transmitted primarily by Aedes aegypti and Aedes albopictus mosquitoes.
Genome and Virology
DENV-3 has a positive-sense RNA genome about 10.7 kilobases long that encodes a single open reading frame. Translation produces a polyprotein that is cleaved into three structural proteins (capsid, premembrane/membrane and envelope) and seven nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5). The envelope protein binds to host cell receptors such as DC-SIGN, and clathrin-mediated endocytosis delivers the virus to endosomes where low pH triggers fusion. RNA replication takes place on endoplasmic reticulum membranes, with the NS5 RNA-dependent RNA polymerase generating negative-strand intermediates and new genomes. Virions assemble in the endoplasmic reticulum and mature in the Golgi before release by exocytosis. DENV-3 infects monocytes, macrophages and dendritic cells in humans as well as midgut and salivary gland cells in mosquitoes. It is divided into several genotypes (I–V) that show distinct geographic distribution and pathogenicity.
Outbreaks and Clinical Significance
DENV-3 has caused notable outbreaks around the world. Genotype III was associated with severe dengue epidemics in Sri Lanka during the late 1980s and in Latin America after reintroduction around 2000. In South Asia and Southeast Asia, periodic waves of DENV-3 infection accompany shifts in serotype dominance and can result in large case numbers. Clinical presentation ranges from asymptomatic to classic dengue fever with fever, headache, myalgia and rash; severe dengue with plasma leakage and hemorrhage occurs mainly in secondary infections, and some DENV-3 genotypes have been linked to increased severity. The virus is maintained in an urban transmission cycle between humans and Aedes mosquitoes and occasionally in sylvatic cycles in non-human primates. Vector control, removal of breeding sites and targeted vaccination are the main preventive measures. Monitoring genetic variation is important to detect emerging genotypes with altered virulence or vaccine escape. DENV-3 continues to circulate across tropical and subtropical regions and contributes significantly to the global burden of dengue. Better understanding of its virology, genotypic diversity and outbreak patterns is essential for improving control and vaccine strategies. Related Terms: Dengue Virus 1, Dengue Virus 2, Dengue Virus 4, Flavivirus, Aedes albopictus