3.7 Analysis of nucleotide and amino acid similarity of SFTSV strain
The two SFTSV strains isolated from patients and the L, S segment sequence of SFTSV isolated from ticks in Dandong City, Liaoning Province and Yanji City, Jilin Province were 100% identical, while the M segment sequence similarity was 99%, which shows that the main source of transmission of SFTS in patients in the Liaoning Province are the ticks distributed in local or nearby areas.
Comparison of the four SFTSV strains with each genotype sequence revealed that it was the closest in nucleotide sequence and corresponding amino acid sequence to genotype A SFTSV (Table 2). The sequence similarities of the isolated L, M, and S nucleotides (and deduced amino acids) with other genetic A-type strains are between 95.95‒100 (98.90‒100), 97.12‒100 (98.32‒100), 95.08‒100 (99.59‒100)%, respectively (Table 3‒5). The nucleotide sequence similarity is above 95%, and the corresponding amino acid similarity is above 98%, which further suggest that the four SFTSV strains are genotype-A strains.