Virome Diversity and Zoonotic Risks of Haemaphysalis concinna Ticks in Northeastern China.

Haemaphysalis concinna is a prevalent tick vector in Northeastern China, exhibiting a broad host range and the capacity to transmit over 40 human pathogens. Although numerous virome studies have investigated this tick species in Northeastern China, individual-level viral prevalence, coinfection dynamics, and the host spectra of the harbored pathogenic viruses remain poorly characterized. In this study, we conducted metatranscriptomic sequencing combined with TaqMan-based real-time quantitative PCR (RT-qPCR) validation on individual ticks to systematically profile the RNA virome of 112 adult H. concinna collected across Northeastern China. A total of 13 RNA viruses spanning six families and one unclassified group were identified, including four confirmed human pathogens, Tick-borne encephalitis virus (TBEV), Dabieshan tick virus (DBSTV), Songling virus (SGLV), and Wetland virus (WELV), alongside one potential human pathogen, Ji'an nairovirus (JANV). Individual-tick RT-qPCR assays revealed an overall viral positivity rate of 46.4%, with prevalence for specific viruses ranging from 0.9% to 13.4%. Notably, multiviral coinfections were detected in 10.7% of ticks (8.9% harboring two viruses and 1.8% harboring three), predominantly involving nairoviruses and rhabdoviruses. Phylogenetic analyses further confirmed that local viral strains clustered closely with endemic pathogenic lineages. Furthermore, literature-based host spectrum analysis demonstrated that these pathogenic viruses possess extensive vertebrate host ranges. Our findings highlight extensive viral diversity, high infection rates, and frequent coinfections in H. concinna, underscoring its pivotal role in maintaining and transmitting emerging tick-borne viruses and emphasizing the heightened risk of zoonotic spillover in Northeastern China.