FIG 1.
Establishment of the cvPCR method and the limits of detection. (A) Authentic SFTSV strain HB29 viral RNA (HB29), the plasmid pCR-SFTSV-posicon (P.C.), which contains the artificial sequence, and the nontemplate control (H2O) were amplified by cvPCR using primer set 1 or 2. The PCR products were digested by EcoRI (+EcoRI). The sizes of the products were estimated by using a 2-log DNA ladder marker (NEB). (B and C) Isolated strains HB29, YG1, and SPL005, expanded in Vero cells, were diluted with serum from a healthy donor. The purified viral RNAs from the dilutions of virus-spiked serum were amplified. The resulting HB29, YG1, or SPL005 was amplified by primer set 1 (B) or 2 (C). The listed values are the dilutions of the viral strains. NTC, nontemplate control.