Roughly 2/3rds of viruses have RNA as opposed to DNA. The term "RNA virus" means that ribonucleic acid is the type of nucleic acid that holds the genome.DNA viruses: adeno, hepadna (hep B), herpes...
Instead of using DNA to infect its' host, it uses RNA. One example of a class/family of RNA virus are retrovirus. The RNA is injected into the host cell and the viral RNA undergoes reverse...