As the human immunodeficiency virus (HIV) disease pandemic surely should have taught us, in the context of infectious diseases, there is nowhere in the world from which we are remote and no one from whom we are disconnected.

1. By 1992, an estimated 8–12 million people worldwide had been infected with HIV. The World Health Organization (WHO) now estimates that there have been 75 million people infected and 32 million deaths, with the majority of cases in Africa.

Consequently, some infectious diseases that now affect people in other parts of the world represent potential threats to the United States because of global interdependence, modern transportation, trade, and changing social and cultural patterns.