Abstract
Dengue fever is perhaps the most important viral re-emergent disease especially in tropical and sub-tropical countries, affecting about 50 million people around the world every year. In the Central Highlands regions of Vietnam, dengue fever still remains as a major public health issue. Although four viral serotypes have been currently identified, dengue virus type 2 (DENV-2) was involved in the most important outbreaks during 2010-2012, especially, 2010 when the fatality rate highly increased. Detection of genotype of DENV-2 provided information on origin, distribution and genotype of the virus. In this study, DEN-2 isolated from dengue patients during the 2010-2012 epidemics was amplified and sequenced with E gene. The consensus sequences were aligned with reference E gene sequences of globally available Genbank. Phylogenetic analysis was performed using Neighbor-joining and Kimura 2-parameter model to construct phylogenetic tree. A total of 15 isolates (seven from 2010; one from 2011 and seven from 2012) were obtained from human serum samples. Phylogenetic analysis revealed that Asian genotype 1 is currently circulating locally in Central Highlands region. Isolates of this genotype were closely related to viruses from Thailand, Laos, and Cambodia. It indicated that these epidemics maybe imported into the Central Highlands region from South-East Asia neighbor countries. The study results would help in planning for prevention and control of dengue virus in Vietnam. Continuous monitoring of DENV genotypes is necessary to confirm the current findings and detect possible genotype shifts within the dengue viruses in the future.
Highlights
Dengue fever (DF) is a mosquito-borne viral infection, transmitted by Aedes aegypti caused major impact on health and economies in subtropical and tropical countries worldwide
dengue virus type 2 (DENV-2) is classified into six genotypes, including two genotypes confined to the Asian population (Asian 1 and Asian 2), the Cosmopolitan, American/Asian, American, and Sylvatic genotype (Twiddy et al, 2002)
Dengue incidence in the Central Highlands: Dengue fever was endemic in the Central Highlands region where all four serotypes of dengue virus (DENV) were co-circulated
Summary
Dengue fever (DF) is a mosquito-borne viral infection, transmitted by Aedes aegypti caused major impact on health and economies in subtropical and tropical countries worldwide. Dengue virus (DENV) is a member of the genus Flavivirus, family Flaviviridae. It is an envelope virus with length 11 kb positive-sense single-stranded RNA genome (Henchal & Putnak, 1990). Dengue fever (DF)/Dengue hemorrhagic fever (DHF) is endemic in the Central Highlands region of Vietnam with all four DENV serotypes co-circulating. The Central Highlands region has a history of outbreaks of dengue viral infection, there is no study reviewing genotype distribution in this region. The current study was aimed to determine the circulating genotype in the Central Highlands using isolates collected from outbreaks of DENV-2 (2010 to 2012), and the obtained sequences were compared to other sequences reported from other geographical regions of the world, to deduce a phylogenetic relationship
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