Emerging infectious diseases (EIDs) represent a global, ongoing threat to the health and livelihood of individuals and communities all over the world, including those in the United States. Despite remarkable progress in healthcare research and treatment during the 20th century, infectious diseases remain the leading cause of death worldwide, causing about 25% of the 57 million annual deaths. This number does not include the millions of deaths that occur as a result of past infections or because of complications from chronic infections. The burden is highest in developing countries, especially affecting infants and children. In developed countries, the mortality disproportionately affects indigenous and disadvantaged minorities (Kaiser Family Foundation [KFF], 2017).
Emerging infectious diseases are defined as “infections that have newly appeared in a population or have existed previously but are rapidly increasing in incidence of geographic range” (Morens, Folkers, & Fauci, 2004, p. 242). EIDs have shaped the course of human history and caused immeasurable misery and death. Originally called “loimos,” “pestilences,” and “plagues,” for centuries humans seemed to be helpless against these sudden epidemics and they struck fear and awe in those who witnessed their devastation (Morens, Folkers, & Fauci, 2004).
History of EIDs
“Outbreaks” today may consist of a few dozen to a few thousand sick or fatally ill individuals. This was not always the case. Throughout history, outbreaks have been so expansive and deadly they essentially changed the course of civilizations and history. Consider these few examples (KFF, 2017; Morens, Folkers, & Fauci, 2004; Oldstone, 2010; Robert Wood Johnson Foundation [RWJF], 2013):
- The Antonine Plague—Named for Roman Emperor Marcus Aurelius Antoninus, this smallpox epidemic occurred in 165 AD and lasted until 180 AD. An estimated 5 million people died in an outbreak believed to have begun in Seleucia (in modernday Iraq) and spread to Rome by soldiers who returned from the city’s siege. At the height of the epidemic, 2,000 Romans a day died from the disease. The emperor was among its victims.
- The Plague of Justinian—In 541 AD, rats in Egyptian grain boats brought the first recorded case of bubonic plague to the modern world. Ultimately, 25 million people died. The Emperor of the Byzantine Empire—Justinian I, for whom the plague was named—contracted the disease and survived. At one point, scholars estimate that as many 5,000 people per day died in Constantinople, the Empire’s capital. At the end of the plague, 40% of the city’s population had perished.