Viruses
Viruses of the family Herpesvirus are notable for remaining dormant within cells in the human body. See, for example, varicella zoster virus, which in an individual causes first chickenpox, then shingles (herpes zoster). Concerning viruses, this dormancy is often referred to as latency or a latent infection. HIV produces a latent infection in lymphocytes, and, at this stage in its life-cycle, it is called a provirus.
This should not be confused with clinical latency.
Read more about this topic: Dormancy