Abstract
Viruses are enormously efficient infectious agents that have been implicated in causing human disease for centuries. Transmission of these pathogens continues to be from one life form to another in the form of isolated cases, epidemics, and pandemics. Each infection requires entry into a susceptible host, replication, and evasion of the immune system. Viruses are successful pathogens because they target specific cells for their attack, exploit the cellular machinery, and are efficient in circumventing and/or inhibiting key cellular events required of survival. This article reviews some of the advances that have taken place in human virology in the past 50 years, emphasizing mechanisms that contribute to, and are involved with, virus survival and persistence.