Evolutionary patterns and heterogeneity of Dengue Virus serotypes in Pakistan

Abstract

Abstract Comprehensive and systematic examination of Dengue virus (DENV) evolution is essential in the context of Pakistan as the virus presents a significant public health challenge with the ability to adapt and evolve. To shed light on intricate evolutionary patterns of all four DENV serotypes, we analyzed complete genome sequences (n = 43) and envelope (E) gene sequences (n = 44) of all four DENV serotypes collected in Pakistan from 1994 to 2023 providing a holistic view of their genetic evolution. Our findings revealed that all four serotypes of DENV co-circulate in Pakistan with a close evolutionary relationship between DENV-1 and DENV-3. Genetically distinct serotypes DENV-2 and DENV-4 indicate that DENV–4 stands out as the most genetically different, while DENV-2 exhibits greater complexity due to the presence of multiple genotypes and the possibility of temporal fluctuations in genotype prevalence. Selective pressure analysis in Envelope (E) gene revealed heterogeneity among sequences (n = 44) highlighting 46 codons in the genome experiencing selective pressure, characterized by a bias towards balancing selection indicating genetic stability of the virus. Furthermore, our study suggested an intriguing evolutionary shift of DENV-4 towards the DENV-2 clade, potentially influenced by antibodies with cross-reactivity to multiple serotypes providing a critical insight into the complex factors shaping DENV evolution and contributing to the emergence of new serotype.