Persistent infections result when the immune system is unable to completely eradicate an infection. Persistent infections are also called chronic infections. These viruses usually cause an initial acute infection lasting a few weeks, followed by a persistent infection with few or no symptoms. During HIV infection, gradual depletion of immune system cells due to their chronic infection by the virus results in immunodeficiency and increased susceptibility to opportunistic infections. Death results from inability to fight off repeated opportunistic infections.
Latent infections are hidden infections.
They differ from persistent infections in that there are long periods when no virus is produced in the body. However, acute attacks may occur. The virus that causes chicken pox, varicella-zoster, also latently infects neurons. Shingles are painful skin rashes that result when the latent virus re-emerges from neurons and infects epithelial cells. A tumor is a solid mass of cells that demonstrate abnormal growth.