Epstein-Barr Virus Infection

Introduction Virtually all humans become infected with Epstein-Barr virus (EBV). The vast majority of these infections are inapparent, occur early in life, and are associated with lifelong latent infection and persistent shedding of virus. Epidemiology The prevalence of antibody to EBV has been determined in many age groups throughout the world. In developing and tropical areas, infection takes place early in life and is inapparent, with most children demonstrating antibody by age 6 years. Infection is believed to be related to hygiene and crowding as well as to cultural patterns that lead to exposure to saliva (eg, prechewing of food). In contrast, infection in Western Europe and the United States in childhood is less common, with only 35% to 50% of 5-year-olds demonstrating antibody. Infectious mononucleosis (IM) emerges as a significant clinical entity only in populations where a sizable percentage of young adults lack immunity to EBV. Thus, IM is unknown among college freshman in Thailand or the Philippines, virtually all of whom have antibody to EBV at the time of admission. On the other hand, in schools in the USA and England, where the susceptibility percentage is in the range of 35% to 50%, infection is seen commonly. In such university settings, approximately 12% of susceptible students become infected with EBV during the freshman year.