Characterization of a novel circo-like virus in Aedes vexans mosquitoes from Germany: evidence for a new genus within the family Circoviridae.

Over recent decades, metagenomic studies have expanded the number of newly described, often unclassified, viruses within the family Circoviridae. Using broad-spectrum circovirus and cyclovirus PCRs, we characterized a novel circo-like virus in Aedes vexans mosquitoes from Germany whose main putative ORFs shared very low amino acid identity with those of previously characterized circoviruses and cycloviruses. Phylogenetic and genetic distance analysis revealed that this new virus species defined, together with previously described mosquito- and bat faeces-derived circo-like viruses, a different genus, tentatively called Krikovirus, within the family Circoviridae. We further demonstrated that viruses of the putative genus Krikovirus all shared a genomic organization that was unique among the family Circoviridae. Further investigations are needed to determine the host range, tissue tropism and transmission route(s). This report increases the current knowledge of the genetic diversity and evolution of the members of the family Circoviridae.