Virome diversity and molecular characterization of two emerging RNA viruses in mosquito populations from Yantai, China

Mosquito-borne viruses represent a major global public health threat, with transmission dynamics governed by climatic, ecological, and anthropogenic factors. Yantai City, Shandong Province, situated in a warm-temperate monsoon climate zone, shares geographical and ecological characteristics with regions where mosquito-borne viruses are endemic, creating potential for virus introduction. We used metagenomics to systematically analyze viral communities in mosquitoes from the Yantai region. We collected 8,111 mosquitoes representing four genera and six species, with <i>Culex</i> being predominant (89.8%). High-throughput sequencing revealed 11 viral species spanning 9 families, including Peribunyaviridae and Picornaviridae. Notably, Serbia mononega-like virus 1 and Biggievirus Mos11 represent the first reports from China, with quantitative reverse transcription PCR revealing minimum infection rates of 0.34% and 0.68%, respectively. Phylogenetic analysis revealed close relationships to known viral strains, with several isolates potentially representing novel genera or species. Analysis revealed that <i>Culex quinquefasciatus</i> harbored the greatest viral diversity (five species), with significantly higher viral diversity in agricultural versus urban areas (<i>P</i> < 0.001). Several viruses demonstrated cross-species transmission potential, including Zhee mosquito virus, Zhejiang mosquito virus 3, and <i>Culex tritaeniorhynchus</i> rhabdovirus, all detected across multiple mosquito species. While most viruses appear mosquito-specific, several show close phylogenetic relationships to known pathogens, potentially posing public health risks warranting surveillance. This study addresses knowledge gaps regarding mosquito-borne viruses in the Bohai Rim region and provides a scientific foundation for regional viral surveillance and early warning systems.IMPORTANCEMosquito-borne viruses are a significant global health threat, with the potential to cause widespread disease outbreaks. This study investigated the viral diversity within mosquito populations in Yantai, China, and characterized the molecular features of two emerging RNA viruses. These findings highlight the remarkable viral diversity harbored by Culex mosquitoes and reveal higher viral diversity in agricultural areas compared to urban settings. Several identified viruses exhibit cross-species transmission potential and close phylogenetic relationships to known pathogens, suggesting that they may pose public health risks. Understanding these interactions is essential for predicting how environmental changes may affect virus transmission and the resilience of surveillance and control strategies.