Ramifications
While viral latency exhibits no active viral shedding nor causes any pathologies or symptoms, the virus is still able to reactivate via external activators (i.e. sunlight, stress) to cause an acute infection. In the case of Herpes simplex virus, which generally infects an individual for life, a serotype of the virus reactivates occasionally to cause cold sores. Although the sores are quickly resolved by the immune system, they may be a minor annoyance from time to time. In the case of varicella zoster virus, after an initial acute infection (chickenpox) the virus lies dormant until reactivated as herpes zoster.
More serious ramifications of a latent infection could be the possibility of transforming the cell, and forcing the cell into uncontrolled cell division. This is a result of the random insertion of the viral genome into the hosts own gene and suppression of host cellular growth factors for the benefit of the virus. A famous event of this actually happening with gene therapy through the use of retroviral vectors is the Necker Hospital in Paris, where 20 young boys received treatment for a genetic disorder, after which 5 developed leukemia-like syndromes .
This is also seen with infections of the human papilloma virus in which persistent infection may lead to cervical cancer as a result of cellular transformation.
In the field of HIV research, proviral latency in specific long-lived cell types is the basis for the concept of one or more viral reservoirs, referring to locations (cell types or tissues) characterized by persistence of latent virus. Specifically, the presence of replication-competent HIV in resting CD4-positive T cells, allows this virus to persist for years without evolving despite prolonged exposure to antiretroviral drugs. This latent reservoir of HIV may explain the inability of antiretroviral treatment to cure HIV infection.
Read more about this topic: List Of Latent Human Viral Infections