Emergence of genotype Cosmopolitan of dengue virus type 2 and genotype III of dengue virus type 3 in Thailand

Abstract

Dengue is a mosquito-borne disease that has spread to over 100 countries. Dengue fever is caused by dengue virus (DENV), which belongs to the Flavivirus genus of the family Flaviviridae. DENV comprises 4 serotypes (DENV-1 to DENV-4), and each serotype is divided into distinct genotypes. Thailand is an endemic area where all 4 serotypes of DENV co-circulate. To understand the current genotype distribution of DENVs in Thailand, we enrolled 100 cases of fever with dengue-like symptoms at the Bamrasnaradura Infectious Diseases Institute during 2016–2017. Among them, 37 cases were shown to be dengue-positive by real-time PCR. We were able to isolate DENVs from 21 cases, including 1 DENV-1, 8 DENV-2, 4 DENV-3, and 8 DENV-4. To investigate the divergence of the viruses, RNA was extracted from isolated DENVs and viral near-whole genome sequences were determined. Phylogenetic analysis of the obtained viral sequences revealed that DENV-2 genotype Cosmopolitan was co-circulating with DENV-2 genotype Asian-I, the previously predominating genotype in Thailand. Furthermore, DENV-3 genotype III was found instead of DENV-3 genotype II. The DENV-2 Cosmopolitan and DENV-3 genotype III found in Thailand were closely related to the respective strains found in nearby countries. These results indicated that DENVs in Thailand have increased in genotypic diversity, and suggested that the DENV genotypic shift observed in other Asian countries also might be taking place in Thailand.

An Epidemic of Dengue Virus Serotype-4 during the 2015 - 2017: the Emergence of a Novel Genotype IIa of DENV-4 in the Philippines

“…Several shifts in the predominant DENV-4 genotype lineages occurred in the Philippines between 2004-2016. In concurrence with other studies in which genotype and lineage turnover coincide with changes in epidemic activity (19,(35)(36)(37)(38), our study demonstrated an increase in the number of DENV-4 patients during the turnover period. While the GIIa lineage in the Philippines forms a distinct lineage, processes of genotype replacement may have been a result of introductory strains and after that on-going local evolution, with the dominance of lineage L3 from the replacement of lineage L2 and sub-lineages within L3 (L3-1-1b).…”

Entomological Surveillance for Zika and Dengue Virus in Aedes Mosquitoes: Implications for Vector Control in Thailand

“…aegypti females caught in 2018 (MN527287-MN527289) were DENV-1 (nucleotide sequence identity > 96%, Figure 2). They were closely related to DENV-1 (LC410183.1) and DENV-4 (LC410203.1) detected in patients from Thailand reported in 2017 [14]. The sequence alignment is shown in Supplementary Figure S2.…”

“…Recently, more than 72,000 dengue cases with a fatality rate of 0.13% were reported in 2018 to the Ministry of Public Health, Thailand. All four DENV serotypes (DENV-1, DENV-2, DENV-3 and DENV-4) are reported to circulate in Thailand with a recurrent circulation of each serotype [12,14,15]. The Department of Disease Control-part of the Ministry of Public Health (MOPH), Thailand-reported that the major DENV serotypes causing illness in 2017 were DENV-1 and DENV-4.…”

Two Cases of Dengue Virus Type 2 (DENV-2) Infection in a Japanese Couple Returning from the Maldives during the 2018 Dengue Outbreak

“…DENV-2 Cosmopolitan genotype was first reported in 1944 in Papua New Guinea and Indonesia (7), and the emergence of DENV-2 Cosmopolitan genotype is widely observed in some countries, such as Pakistan and Thailand (8,9). As DENV-2 serotype is associated with severe dengue infection (10), its international spread could be a menace for global health.…”