Evidence for virus-derived DNA and host–virus chimeric events generating in mosquito cell cultures following infection with dengue virus serotype 1

Dengue virus (DENV), a mosquito-borne flavivirus, establishes persistent infections in Aedes vectors, yet the mechanisms underlying viral persistence and potential genomic integration remain poorly understood. Here, we established in vitro models using Aedes albopictus C6/36 and Aedes aegypti Aag2 cells to investigate DENV-1-derived viral DNA (vDNA) formation and integration. Our results demonstrated that vDNA production is initiated at Day 3 postinfection in C6/36 cells and Day 5 in Aag2 cells, revealing cell-specific temporal dynamics in vDNA generation. Importantly, we detected DENV-1 vDNA in wild-caught Ae. albopictus from Guangzhou, confirming its presence in natural mosquito populations. To further explore viral integration, we constructed genome walking libraries for both cell lines and employed genome walking combined with high-throughput sequencing, which provided direct evidence of DENV-1 sequence integration into the Ae. albopictus genome. These findings not only elucidate the kinetics of vDNA production in mosquito cells but also highlight the potential role of vDNA in facilitating viral genome integration, offering new insights into the long-term host–pathogen interactions and the evolutionary dynamics of arboviruses in their vectors. This study advances our understanding of DENV persistence mechanisms and highlights the need to further investigate the biological implications of viral integration in mosquito populations.