# Genomic Characterization of Dengue Virus in the Ningxia Hui Autonomous Region, China (2019 and 2023)

## TL;DR

This study analyzes the genomic data of dengue virus in Ningxia, China, revealing insights into its origins and mutations over time.

## Contribution

The study provides the first genomic characterization of DENV-1 in Ningxia and identifies key mutations affecting vaccine and antibody interactions.

## Key findings

- The 2019 Ningxia DENV-1 strains are closely related to those from Hebei, while the 2023 strain is similar to viruses from Yunnan and Guangdong.
- The most recent common ancestor of the Ningxia strains is estimated to have existed around 1989, shared with strains from Guangdong, Yunnan, and Southeast Asia.
- Amino acid substitutions in the prM–E proteins and an epitope mutation (N52D) suggest potential impacts on vaccine and antibody efficacy.

## Abstract

Dengue virus (DENV) transmission has risen across China in recent years, but genomic data from inland regions remain scarce. We screened 9 clinical samples collected in Ningxia in 2019 and 2023, obtaining 5 near-complete DENV-1 genomes, and performed phylogenetic reconstruction and molecular clock analyses using a global dataset of 452 DENV-1 sequences to infer spatiotemporal origins; epitope divergence relative to vaccine strains and human monoclonal antibodies was also assessed. The 2019 Ningxia strains clustered within DENV-1 genotype I, clade E, and were closely related to viruses from Hebei Province, whereas the 2023 strain fell within genotype I, clade K, showing the highest similarity to sequences from Yunnan and Guangdong. The most recent common ancestor of the Ningxia strains was estimated to have existed around 1989 (95% highest posterior density: 1985–1993) and is shared with strains from Guangdong, Yunnan, and Southeast Asia. Comparative analysis of prM–E proteins identified 16 (2019) and 11 (2023) amino acid substitutions relative to the vaccine strain, and E-protein epitope mutation (N52D) is predicted to alter binding to the neutralizing antibody 1F4. These findings establish a molecular baseline for origin tracing and proactive surveillance in northwestern China.