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Virus evolution during a severe dengue epidemic in Cuba, 1997
Rosmari Rodriguez-Roche1, Mayling Alvarez, Tamara Gritsun
1Department of Virology, PAHO/WHO Collaborating Center for Viral Diseases, Pedro Kourí Tropical Medicine Institute, Autopista Novia del Mediodía, Km 6, PO Box 601, Marianao 13, Havana, Cuba.
Virology
|March 23, 2005
Summary
Genomic sequencing of Dengue virus type 2 (DENV-2) during a 1997 Cuban outbreak revealed evolutionary changes in non-structural genes, particularly NS5. These viral evolution patterns may influence disease severity, warranting further investigation.
Area of Science:
- Virology
- Molecular Biology
- Epidemiology
Background:
- Dengue virus type 2 (DENV-2) caused a significant outbreak in Cuba in 1997.
- Understanding viral evolution during epidemics is crucial for public health.
- Genomic analysis provides insights into viral adaptation and pathogenicity.
Purpose of the Study:
- To determine the full-length genomic sequences of DENV-2 isolates from the 1997 Cuban outbreak.
- To analyze the phylogenetic relationships and evolutionary patterns of these DENV-2 isolates.
- To identify genetic changes associated with DENV-2 evolution during the epidemic.
Main Methods:
- Whole-genome sequencing of six DENV-2 isolates.
- Phylogenetic analysis to determine genotype and evolutionary relationships.
- Comparative genomic analysis of conserved and variable regions.
Main Results:
- All six DENV-2 isolates belonged to the "American/Asian" genotype.
- Structural proteins and non-coding regions (5' NCR and 3' NCR) showed high conservation.
- Non-structural genes, especially NS5, exhibited nucleotide substitutions.
- A temporal evolutionary pattern was observed, with earlier isolates differing from later ones in NS1 and NS5 protein sequences.
- No evidence suggested these amino acid replacements were escape mutants.
Conclusions:
- DENV-2 isolates from the 1997 Cuban outbreak evolved during the epidemic.
- Amino acid changes in NS1 and NS5 proteins mark this evolution.
- The functional significance of these replacements and their link to disease severity require further research.