We analyzed for hematological profile and tittered viremia as previously described (17 (link)). Total white blood cell and platelet counts in whole ferret blood samples were analyzed using the Celltac hematology analyzer (MEK-6550J/K, Nihon Kohden, Japan). Total RNA was extracted with TRIzol reagent (ThermoFisher) and reverse-transcribed to generate cDNA using QuantiTect Reverse Transcription system (Qiagen). Primers for real-time RT PCR (F: AATTCACATTTGAGGGTAGTT), R: TATCCAAGGAGGATGACAATAAT) were designed to recognize M segment of DBV genome. Real-time PCR was performed with SYBR Green supermix and CFX Real-Time PCR detection system (Bio-Rad). Copy numbers were normalized to GAPDH gene.