Phylogenetic characteristics of the pathogen of severe HFRS
The sequences were BLAST and aligned with related sequences to infer the phylogenetic location of the virus. The SFTSV positive product exhibited sequence homology of 98.11% with SFTSV isolated from ticks in SFTS patients and endemic regions in our lab in 2019 (NCBI accession: MT 232961.1), consisting of genotype A with minimal mortality[11]. The HTNV sequences derived from specimens of severe patients (No 2, 5, and 6) indicated that patient No. 5 and No. 6 share identical DNA, while Patient No. 2 possessed a unique sequence. Appendix 2 illustrates the DNA sequence of Patient No. 2, with specific bases highlighted in sequences 5 and 6. Homeland and international reference strains sourced from the NCBI website served as reference sequences for construction of the phylogenetic tree using MEGA7.0. The results showed an affinity with strains KC576787 and KC5767862 (both isolated in Jilin Province) at 94.78%. The phylogenic tree of HTNV is shown in Figure 1.