Fig 1.
Comparison of the topological structures of the ML trees of S, M, and L segments.
A, B, and C were the topological comparison results of the S - M, M - L, and S - L segments of SFTSV, respectively. When the names of the leaf nodes were consistent, they were connected by blue dashed lines. Genotyping was carried out based on the topological comparison results, and types A - E were represented by different colors in the figure.
Fig 2.
Phylogenetic analysis of full-length genomic segments of SFTSV strains.
ML trees were constructed using S (A), M (B) and L (C) segment sequences and tested by bootstrap analysis over 1000 iterations. The five genotypes represented by cyan, green, purple, blue, and orange are classified as ABCDE genotypes, while black is designated as the unassigned type. The geographic distribution of these genotypes is illustrated by color blocks of varying hues. In instances where Liaoning province collected data exclusively with M segments and Jilin province collected data exclusively with L and S segments, these genotypes are represented by a single color to facilitate comparison.
Fig 3.
Sequence geographic distribution and reassortment event statistics.
A shows the sampling locations of all strain sequences and the distribution locations of reassorted strains in S1 Table. We filled each province with orange, and the shade of the color indicates the quantity of sequences. B presents a pie chart illustrating the genotype percentage of sequences in L, M, and S in each region. It should be noted that only the M segment is available for the data collected in Liaoning Province, while only the L and S segments are available for the data collected in Jilin. The base layer of the map was made with Natural Earth (naturalearthdata.com), distributed openly under the following terms and conditions: https://www.naturalearthdata.com/about/terms-of-use/.
Fig 4.
The genetic constellation of the potential SFTSV reassortments.
Each genotype is represented by a distinct color, with the L, M, and S segments indicated by varying line lengths. The black line represents unassigned. The name of each sequence with a potential reassortment event is provided below the corresponding graphic.
Table 1.
Host statistics for SFTSV sequences.
Fig 5.
Figure of the range of breakpoints for L, M, and S segments of potential recombination sequences of SFTSV.
The blue circle represents the initial position of the recombination breakpoint, the orange circle represents the final position of the recombination breakpoint, and the middle line represents the recombination range. The figure also provides the number of each recombination sequence and the corresponding GenBank number at the bottom.
Fig 6.
MCC tree and predicted SFTSV migration paths.
A: Maximum clade credibility tree with branches colored by discrete geographic regions is presented. Color bars indicate hosts and subtypes. B: Discrete systematic geographic reconstruction of SFTSV propagation during 1785-1980. C: Discrete systematic geographic reconstruction of SFTSV propagation during 1980-2023. The direction of the arrows in B and C indicate the propagation routes, and the colors indicate the different export areas (the color scheme is consistent with that used in A). The mauve and light blue areas indicate the migratory routes of birds in central and eastern China. The base layer of the map was made with Natural Earth (naturalearthdata.com), distributed openly under the following terms and conditions: https://www.naturalearthdata.com/about/terms-of-use/.