Dissecting the Evolutionary Forces Shaping Codon Usage Bias in SFTSV from eastern China: Insights from a Previously Underrepresented Region

Viral RNA was isolated from a serum sample using a QIAamp viral RNA Mini Kit (Qiagen) and subjected to quantitative reverse-transcription polymerasechain-reaction (qRT-PCR) targeting the S segment of SFTSV. Nested RT–PCR assays were performed on viral RNA with CT values of qRT-PCR ≤ 32, to obtain a full-length genome sequence of SFTSV. In brief, a total of 19 pairs of primers covered whole genomic sequences of SFTSV were used for the first round of amplification with the PrimeScript OneStep RT–PCR Kit (Takara), and 19 pairs of primers were used for the second round of amplification with the DreamTaq Green PCR Master Mix (Thermo Scientific). PCR amplicons were purified and sequenced on a 3730 DNA Sequencer (Applied Biosystems).