The risk of pathogenic tick-borne viruses in Northeast Asia: a genomic and ecological modelling study

The prevalence, epidemiological history and disease risk posed by pathogenic tick-borne viruses (TBVs) remain poorly understood in Northeast Asia. Here, over 12,000 ticks were collected from diverse ecological environments in Northeast China, leading to the identification of 44 TBVs from which 1,221 viral sequences were assembled. This included six human/mammal-infecting TBVs: Alongshan virus, Beiji nairovirus, Mukawa virus, Nuomin virus, tick-borne encephalitis virus (TBEV), and Yezo virus. Aga, Izumo, and Nishinomiya in Japan were identified as tick diversity hotspots, while Shangzhi City, Genhe City, and Raohe County in China were classified as TBV hotspots. We then performed an ecological modelling of seven human-infecting TBVs and their major tick species. Both TBVs and their tick vectors were projected to have a wider distribution potential than previously recognized, including the human-infecting Wetland virus (WELV) identified in 2024. Notably, aside from WELV, the other six human-infecting TBVs were predicted to circulate in all five Northeast Asian countries. Specifically, severe fever with thrombocytopenia syndrome virus was projected to potentially impact 266.74 million people, including nearly 100% of the population of Liaoning of China, the Republic of Korea (ROK) and the Democratic People's Republic of Korea (DPRK), and 91.6% of the Japanese population. TBEV was modelled to have the widest distribution potential area of 8.56 million km² (95.4%), potentially impacting 226.65 million people (71.1%). Overall, our study highlighted Northeast China and its adjacent countries as high-risk regions for several human-infecting TBVs. It is imperative to prioritize preventive and therapeutic measures for these high-risk TBVs.