Course of GBV-B infection in S. mystax tamarins selected for further analysis of GBV-B evolution. The animals became infected following intrahepatic transfection with RNA transcripts of pGBB-A669N (SM908 and SM910), pGBB-R654L-R704L (SM916 and SM917), pGBB-A681R (SM911 and SM912), pGBB-R704L (SM920) and pGBB-A680L (SM918) (Takikawa et al., 2006). Serum levels of ICD (shaded area) and the estimated GBV-B titre (◊), determined in a TaqMan quantitive PCR assay, were plotted against time. Samples found to be below the assay cut-off of approx. 103 genome equivalents ml−1 in the TaqMan assay are shown as not detected (nd). The complete ORF sequence of recovered GBV-B virus was determined at the weeks indicated by arrows.