Abstract
BACKGROUND: Hemorrhagic fever with renal syndrome (HFRS) is highly prevalent in northeastern China, especially along the borders with Russia and North Korea. However, the prevalence of HFRS-causing orthohantaviruses in rodents in these regions remains unclear. METHODS: Rodents were captured across the tri-border region. Lung tissues were collected to detect human-pathogenic Hantaan virus (HTNV), Seoul virus (SEOV), and Amur virus (AMRV). Complete viral genome sequences from positive samples were amplified for phylogenetic and homology analyses. RESULTS: A total of 430 rodents from four species were captured from five villages in the tri-border region, with Apodemus agrarius as the dominant species, accounting for 41.4%. HTNV was detected in 8.4% of A. agrarius and 3.6% of R. norvegicus individuals, with viral loads ranging from 2.2-6.9 log₁₀ copies/μL and 4.1-6.9 log₁₀ copies/μL, respectively. AMRV was identified in 6.3% of A. peninsulae individuals, with viral loads between 3.6-6.7 log₁₀ copies/μL. SEOV was not detected in any samples. No significant differences in viral prevalence were observed across years, seasons, or collection habitats, nor in viral load between virus species or rodent species. One AMRV and ten HTNV complete genome sequences were successfully obtained. Phylogenetic analysis revealed that the identified HTNV strains formed a distinct clade with previously reported strains from northeastern China and Russia, showing nucleotide and amino acid similarities of 87.5-97.6% and 97.1-100.0%, respectively. AMRV exhibited a close evolutionary relationship with strains isolated from patients and from A. peninsulae in China, displaying nucleotide and amino acid similarities of 80.6-84.7% and 92.3-97.7%, respectively, compared to HTNV. CONCLUSIONS: Our study confirms natural infections of HTNV in A. agrarius and R. norvegicus, and of AMRV in A. peninsulae, in the tri-border region of China, Russia, and North Korea. Further epidemiological studies on orthohantavirus infections in humans and rodents are warranted in this border region.