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Background: The evolutionary dynamics of dengue virus type 1 (DENV-1) in non-endemic settings such as southeastern coastal China where outbreaks predominantly stem from imported cases, remains insufficiently defined, particularly in relation to lineage displacement dynamics.
Methods: Ninety-three DENV-1 isolates (56 from 2019, 37 from 2024) collected in southeastern coastal China underwent whole-genome sequencing. Phylogenetic relationships were inferred using maximum likelihood methods under the GTR + G + I model. Selection pressures were assessed through FEL, MEME, SLAC, and FUBAR. Recombination was analyzed using seven detection algorithms implemented in RDP4. Hamming distances were used to profile amino acid substitutions. Epitope mapping was performed by comparative alignment against CYD-TDV and TAK-003 vaccine reference strains.
Results: Phylogenetic inference placed all isolates within genotype I, yet 2019 and 2024 sequences segregated into distinct clades: 1I_E.1 and 1I_K.2, respectively. Codon-level analyses consistently indicated purifying selection. Eighteen recombination events were identified, predominantly involving strains of Vietnamese and Cambodian origin. A total of 40 non-synonymous substitutions were conserved across both periods, while 24 mutations were exclusive to 2024 isolates, with marked enrichment in NS3 and NS5 proteins. Epitope analyses revealed 9 and 17 antigenic variants within neutralizing domains of CYD-TDV and TAK-003, respectively.
Conclusion: Complete genotype turnover of DENV-1 occurred in southeastern coastal China between 2019 and 2024, driven by displacement of lineage 1I_E.1 by 1I_K.2, with implications for local transmission patterns. Observed antigenic divergence between temporal isolates emphasizes the importance of sustained genomic monitoring and targeted intervention strategies tailored to circulating strains in this region.
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http://dx.doi.org/10.3389/fmicb.2025.1607085 | DOI Listing |
Mar Pollut Bull
September 2025
School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen, 361021, China; Xiamen Key Laboratory of Membrane Research and Application, Xiamen, 361024, China. Electronic address:
With the rapid economic development of coastal cities, the discharge of significant amounts of heavy metal pollutants has posed a severe threat to mangrove forests. However, the potential sources of these metals and the health risks they pose remain poorly understood. This study analyzed 14 heavy metals in mangrove and river sediments of Zhangjiang Estuary, southeastern China.
View Article and Find Full Text PDFJ Hazard Mater
September 2025
State Key Laboratory of Advanced Environmental Technology, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China. Electronic
Surface ozone (O) pollution has emerged as a regional environmental issue. Photochemical reactive species significantly impact O photochemical formation by regulating radicals and atmospheric oxidation capacity. This study focuses on O pollution in a southeastern coastal city, utilizing coordinated methods of filed observations and Photochemical Box Model to explore the pollution mechanisms and sensitivity analyses of typical reactive species (PAN, HCHO, and isoprene).
View Article and Find Full Text PDFBiology (Basel)
August 2025
Palm Beach Gardens, Palm Beach State College, 395 Mallard Pt., Jupiter, FL 33458, USA.
Gopher tortoises () are threatened burrowing keystone ecosystem engineers indigenous to open uplands in the Southeastern United States. Perils to the species include habitat degradation and fragmentation, anthropogenic disturbances, predation, parasites, and disease. Problems are severe in the SE Florida study area due to coastal urban sprawl, confining the tortoises in small, scattered, unnatural pockets subject to novel stresses.
View Article and Find Full Text PDFForested, freshwater tidal wetlands in the southeastern US are dominated by bald cypresses (), which tolerate low levels of salinity. However, the response of old-growth bald cypress trees to prolonged increases in salinity remains uncertain. Bald cypress ghost forests occur along Smith Creek, a tributary of the Cape Fear River, North Carolina which has been dredged multiple times since 1871.
View Article and Find Full Text PDFMar Environ Res
August 2025
College of Marine Life Sciences, Ocean University of China, 266003, Qingdao, China. Electronic address:
China's southeastern coast, particularly Zhejiang, Fujian, and Guangdong, is rich in key fishery resources but also faces elevated contamination due to intensive industrial activity. The study investigated the spatial and temporal variations of mercury (Hg) in Bombay duck (Harpadon nehereus) collected from five coastal sites, the Yangtze River estuary, Hangzhou Bay, Wenzhou, Xiamen and Zhanjiang. The Hg levels and MeHg/THg ratios generally increased with decreasing latitude, with the highest Hg concentrations observed in Zhanjiang (THg: 0.
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