Comparative evolutionary epidemiology of dengue virus serotypes

Area of Science:

• * Molecular epidemiology
• * Viral evolution
• * Dengue virus (DENV) serotypes

Background:

• * Previous dengue virus evolutionary studies often concentrated on intra-serotype diversity or specific outbreaks.
• * A comprehensive understanding of evolutionary molecular epidemiology across all DENV serotypes is lacking.

Purpose of the Study:

• * To conduct an extensive comparative study of the evolutionary molecular epidemiology of dengue virus serotypes.
• * To investigate the drivers of DENV serotype diversification, including adaptive changes versus stochastic events.

Main Methods:

• * Compilation of a comprehensive dataset of the DENV envelope (E) gene sequences.
• * Comparative analysis of evolutionary rates and population dynamics using Bayesian coalescent methods.
• * Assessment of selection pressures on the E gene.

Main Results:

• * Identified homogeneous substitution rates across all DENV serotypes.
• * Inferred differing population dynamics among serotypes, with DENV-2 exhibiting the largest effective population size globally.
• * Observed clear geographical structuring within the genealogies of each serotype.
• * Found significant purifying selection acting on the DENV E gene.

Conclusions:

• * DENV serotype diversification may be attributed to stochastic events rather than solely adaptive changes.
• * The findings provide insights into the evolutionary history and population structure of dengue viruses, crucial for public health interventions.