Molecular Characterization of Dengue Viruses Imported Into Taiwan during 2003–2007: Geographic Distribution and Genotype Shift

Abstract

We presented our surveillance results on imported dengue cases in Taiwan during 2003-2007. A total of 542 imported dengue patients were identified. The travelers were infected in 17 countries in Southeast Asia, the Indian subcontinent, East African islands, South Pacific islands, and Central America. Most of these imported cases were infected in Southeast Asian countries. Phylogenetic analyses were conducted to examine 288 imported dengue virus (DENV) strains introduced from 13 countries. The results provide an updated view on the geographic distribution and dynamic transmission of epidemic DENV stains circulated in Southeast Asian countries. Although the geographic distributions of genotypes of DENV-3 isolated from Southeast Asian countries remain unchanged, the introductions and local expansions of epidemic DENV-1, DENV-2, and DENV-4 strains into new areas in Asia were observed. These findings highlight the importance to strengthen laboratory-based dengue surveillance for better understanding of transmission dynamics and molecular evolution of DENVs.

Laboratory-Based Surveillance and Molecular Characterization of Dengue Viruses in Taiwan, 2014

“…27 Genotype I of DENV-1 and the cosmopolitan genotype of DENV-2 were the most prevalent DENV strains isolated from imported dengue cases arriving from Southeast Asian countries in 2014, which corresponds to the results of studies conducted over the last decade. 14,15 Interestingly, a DENV-2 strain isolated from a case imported from Tuvalu had the cosmopolitan genotype and is closely related to viral strains from Fiji, which suggests that these viruses were co-circulated between these two nations. In addition, a DENV-2 strain isolated from a case imported from Saudi Arabia had the cosmopolitan genotype and is closely related to viral strains from South and Southeast Asian countries (Figure 4).…”

“…Primers used for amplification and sequencing of E gene sequences of DENV were described previously. 13,14 RT-PCR was performed using the SuperScript III One-Step RT-PCR System with Platinum Taq High Fidelity (Invitrogen, Life Technologies, Carlsbad, CA). The complementary DNA synthesis step was performed at 55°C for 30 minutes.…”

“…Most of the epidemic strains were introduced from neighboring Asia-Pacific countries through air travel. [13][14][15][16] To reduce the introduction of DENV strains into Taiwan and prevent local outbreaks, both passive (hospital-based reporting systems) and active surveillance systems (such as fever screening at airports and seaports, self-reports, and expanded screening for contacts of confirmed cases) have been implemented by central and local health departments. Samples of suspected dengue cases were submitted for laboratory diagnosis and confirmation.…”

Molecular Characterization and Phylogenetic Analysis of Dengue Viruses Imported into Taiwan during 2008–2010

“…With the increase in worldwide travel, the rapid expansion of DENV strains to different parts of the world has been well documented. [8][9][10][11][12][13][14] Studies on imported dengue cases can provided useful information for the geographic distribution and global movement of DENV strains.…”

Dengue virus presence and surveillance in Okinawa (Review)

“…Although there are four distinct serotypes (DENV1 to DENV4), molecular analysis during [2003][2004][2005][2006][2007] showed that the geographic distribution of DENV3 strains and genotypes isolated from southeast Asian countries remained unchanged during [2003][2004][2005][2006][2007], whereas the movement and establishment of new DENV1, DENV2 and DENV4 strains were observed in certain areas of Asia (21). Among them, DENV2 and DENV3 genotypes are frequently associated with severe disease accompanying secondary infection, known as antibody-dependent enhancement (2).…”