BF2 cells were transfected with 5 μg of plasmid encoding the respective viruses, or infected with SAVH20/03. Supernatant was passed to new CHSE cells three times. All viruses were detected by IFAT using anti E2 antiserum, except EGFPrSAVnsP3mut and EGFPrSAV3 which were directly detected by fluorescence microscopy. The relative amount of positive cells for each virus is indicated (-/+/++/+++). SAVH20/03 served as positive control. ND = Not done.