Fig. 1. Stages of RNA and DNA virus replication. Attachment of virus to susceptible cells is followed by penetration and uncoating. Most DNA viruses undergo transcription, replication, and assembly in the nucleus. The DNA virus shown is released from the cell by lysis. Most RNA viruses replicate in the cytoplasm. The dashed line illustrates the transcription pathway of the negative-stranded viruses, and the solid line indicates the pathway taken by the positive-sense RNA viruses. The RNA virus shown is released from the cell by budding through the plasma membrane. (Stroop WG: Fundamentals of neurotropic viruses. In McKendall RR, Stroop WG [eds]: Handbook of Neurovirology, p 5. New York, Marcel Dekker, 1994.)