Molecular epidemiology and phylogeographic insights into Dabieshan tick virus in South Korea

Dabieshan tick virus (DBTV) is a recently identified phenuivirus transmitted by ticks and has been reported across East Asia, raising concerns regarding its epidemiological and public health significance. In South Korea, DBTV was first detected in 2021, yet its genetic and epidemiological characteristics remain poorly understood. Between 2024 and 2025, a total of 1039 ticks collected from vegetation across nine regions in South Korea were grouped into 287 pools and screened for phenuivirus infection. DBTV was detected in 34 tick pools, yielding an overall minimum infection rate of 3.3%, and was identified in all surveyed regions, indicating widespread circulation. Phylogenetic analyses of the L and N genes showed that South Korean DBTV strains clustered closely with strains from multiple provinces in China and from Japan, with high nucleotide sequence similarity. Selection pressure analyses indicated predominant purifying selection acting on both genes. However, several positively selected sites and potential recombination signals were detected in the L gene, suggesting limited but ongoing genetic diversification. Time-scaled Bayesian phylodynamic analyses estimated that the most recent common ancestor of the South Korean DBTV strains have emerged around 2015-2016. Phylogeographic reconstruction further supported the introduction of DBTV into South Korea from Hubei Province, followed by regional dissemination. Overall, this study provides molecular epidemiological evidence for the circulation and evolutionary history of DBTV in South Korea and highlights the need for continued surveillance.