The ability of some viruses to remain inactive (latent) for a period of time is exemplified by

Herpe simplex virus 

Herpes simplex viruses can also be refers to as human herpes virus 1 and 2 and these virus commonly spread when an infected person is shredding and producing the virus. The herpes virus is made up of double stranded linear DNA genomic enclosed within an icosahedral protein called the capsid. Thus, there production is triggered by the development of emotional or phycological  stress by the host.

amber has allowed scientists to study dna that has been preserved over millions of years.