Dengue Virus Seroprevalence and Genetic Diversity: Investigation of Recent Dengue Outbreaks in Nepal

Dengue virus (DENV) was first detected in Nepal in 2004 since then, outbreaks have occurred regularly and become progressively more severe. The outbreaks are marked by changes in clinical symptoms and disease severity; shifts in dominance of the four serotypes (DENV1 to 4) and increases in geographic spread, suggesting that there is high chance dengue becomes hyperendemic in Nepal. However, little is known about how DENV genetic evolution may be associated with altered viral and epidemiological dynamics in successive outbreaks. Here, we propose to fill this knowledge gap by testing our hypothesis that the genetic evolution of DENV shapes the serotype dominance, seroprevalence, and, possibly, clinical manifestations, using blood samples collected from 853 Nepalese patients during the 2019 and 2022 outbreaks. In Aim 1, we will examine the distribution of DENV NS1 antigen, anti-DENV IgG, and anti-DENV IgM (by ELISA) anti DENV neutralizing antibodies (byPRNT assay) and DENV serotype prevalence (RT qPCR) across various demographic parameters. In Aim 2, we will perform whole genome sequencing of DENV in RT qPCR positive samples (Aim 1) to identify and track genomic changes (Illumina MiSeq platform).The results of this study will increase our understanding of how genetic changes in DENV may have influenced the serotype distribution, seroprevalence, and key clinical features during the 2019 and 2022 outbreaks in Nepal. This pilot study may also help to guide healthauthorities in developing targeted mitigation strategies against DENV, bolstering the local healthcare infrastructure, and creating a vital biobank for continued DENV.