Ticks are crucial vectors for various pathogens associated with human and animal diseases, including viruses. Nevertheless, significant knowledge gaps prevail in our understanding of tick-borne viruses (TBVs). We here examined existing studies on TBVs, uncovering 870 documented virus species across 28 orders, 55 families, and 66 genera. The discovery history, vector ticks, and hosts of TBVs, as well as the clinical characteristics of TBV-induced diseases, are summarized. In total, 176 tick species from nine tick genera were confirmed as vectors for TBVs. Overall, 105 TBVs were associated with infection or exposure to humans and animals. Of them, at least 40 were identified to cause human or animal diseases. This review addresses the current challenges associated with TBV research, including the lack of knowledge about the identification of novel and emerging TBVs, the spillover potentials from ticks to hosts, and the pathogenicity and infection mechanisms of TBVs. It is expected to provide crucial insights and references for future studies in this field, while specifically focusing on expanding surveys, improving TBV identification and isolation, and enhancing the understanding of TBV–vector–host interactions. All of these findings will facilitate the preparation for preventing and treating diseases caused by emerging and novel TBVs.

Tick-borne encephalitis virus (TBEV) is a pathogen that causes febrile infectious diseases and neurological damage to humans. TBEVs are prevalent from Europe to Far Eastern Asia, including Northeastern China. The understanding of TBEV phylogeny in China has been limited owing to insufficient genomic data on Chinese TBEV strains. Here, six TBEV strains were isolated from ticks collected in Inner Mongolia. The transmission electron microscopy revealed spherical particles with an enveloped structure of 50-60 nm in diameter. Phylogenetic analysis showed that, two strains were classified as the Siberian subtype, while the remaining four were identified as the Far Eastern subtype. Migration analyses based on TBEV ORF and envelope (E) protein sequences revealed that Chinese TBEV strains were migrated from Russia and/or Kazakhstan into China. Hulun Buir and Mudanjiang, the northeastern region of China, are considered hotspots with multiple import and export routes of Chinese TBEV strains. These results promote the understanding of TBEV genetic variations and phylogeny in China and suggest the importance of improving investigation of TBEV prevalence, which would instrumental for vaccine design strategies and better preparation for controlling TBEV infection in humans.