Chijiahe virus, a novel mosquito-associated virus of the Iflaviridae family found in Shandong Province, China

Climate change is increasing the threat of arboviruses globally, amplifying their geographic distribution and virulence. This poses a grave risk to public health as mosquito-transmitted viral infections resurge and spread. Unbiased metagenomics plays a crucial role in identifying unknown pathogens and monitoring significant ones. Using this approach, a novel mosquito-associated virus, named Chijiahe virus, was discovered. We collected 2910 mosquitoes and divided them into 65 pools based on species and collection site. To ascertain the existence of Chijiahe virus, we utilized nested PCR alongside real-time quantitative reverse transcription PCR (RT-qPCR). Further analysis of the virus's genomic characteristics and phylogenetic relationships revealed its detection in 10 out of 65 mosquito pools, yielding a minimum infection rate (MIR) of 0.34 %. The virus genome consists of a 9654-nucleotide single-stranded RNA, containing an open reading frame (ORF) that encodes essential proteins, including the capsid protein, RNA helicase, and RNA-dependent RNA polymerase (RdRp). Pairwise distance analysis revealed high nucleotide identity among all obtained sequences. Phylogenetic analysis demonstrated Chijiahe virus's close relationship to Arthropod iflavirus, a member of the family <i>Iflaviridae</i>. Additional analyses confirmed Chijiahe virus as a novel member of <i>Iflaviridae</i>.