text: what is the difference between a rna and dna virus?   a rna virus is usually the one which has either single or double stranded strands of rna & are usually the viruses which affect & cause majority of the infections in the world by affecting either animals, plants & humans. hiv is one such example. dna viruses on the other hand may have a single or double stranded dna & usually are less infectious than the rna viruses. however, both can cause life threatening diseases.  in either cases a virion which is the dormant/nonliving,passive form of the virus which is nothing but rna/dna wrapped in a protein coat & carrier of it on finding a suitable host will infect it by attaching to a specific receptor on the host cell.  after infection, only the rna/dna of the virus enters the host cell & replicate via various mechanisms using the hosts machinery & energy for repliction, sometimes involving a suitable intermediate. when sufficient copies of the rna/dna have been made, the virus lyses the host cell & finds other host cells killing the previous host cell. sometimes the virus may even get replicated with the host cell itself by incorporating ita dna with the hosts dna & this is called lysogeny.  eg of dna viruses.-- herpes simplex virus "  " rna viruse-- hiv virus.