Zefeng DONG ^* Man Yuan ^* Yueping Xing ^* HongKai Zhang Qiang Shen ^*

• Suzhou Centre for Disease Control and Prevention, Suzhou, China

Background Ten cases with Dabie bandavirus infection were identified in Suzhou City, China from April 2023 to August 2024. All ten cases were hospitalized patients, and three died. We detected and analyzed cytokines concentrations and viral genomes in serum samples of these patients to identify the possible causes of the patients' deaths and to analyze the viral genetic characteristics.Methods Blood serum specimens were obtained from the ten individuals with Dabie bandavirus infection in Suzhou City. The specific nucleic acid of Dabie bandavirus was detected using a real-time reverse transcription polymerase chain reaction assay (RT-qPCR). The cytokines concentrations in serum were detected by micro enzyme-linked immunosorbent assay (ELISA). The genomes of Dabie bandavirus were amplified using a designated primer pool. The DNA sequencing libraries were prepared using a ligation method. The sequencing process was performed using a Nanopore GridION X5 instrument. Phylogenetic trees for the L, M, and S segments of Dabie bandavirus were constructed using the Maximum Likelihood (ML) method in MEGA 11 software, with the bootstrap value set at 1000. Results All ten patients with Dabie bandavirus infection exhibited severe clinical course, resulting in three fatalities. The cytokines concentrations of CCL2, GM-CSF, IFN-γ, IL-1β, IL-6, IL-8, and TNF-α were significantly elevated in fatal patients compared with recovered cases, all p values for these cytokines analyses were under 0.05. The Dabie bandavirus strains identified in Suzhou belonged to three distinct genotypes: A, B, and F. The nucleotide identities for the L, M, and S segments were 95.65%-99.76%, 93.73%-99.81%, and 94.62%-99.88%, respectively. The average evolutionary rate of segment S was higher than that of segment M and segment L. A recombination event was identified in SZ03-TXF strain. High viral load and cytokines storm may be associated with the case fatality of Dabie bandavirus infection. We should strengthen the monitoring of nucleotide substitutions and conduct health education for high-risk populations, so as to effectively prevent and control an epidemic of the Dabie bandavirus infection in the future.