Date of this Version
May 2016 / Vol. 66 No. 5
The emergence of novel or previously rare pathogens is not new. Throughout recorded history, catastrophic mortality has followed the arrival of new infectious diseases to areas that had no previous experience with the offending agent. The second plague pandemic, more commonly known as the Black Death, was caused by a bacterium that originated in China but then spread throughout Asia, Europe, and Africa via the Silk Road and other routes of commerce. The emergence of rinderpest in Africa, associated with Asian cattle imported by European colonists, killed millions of domestic livestock and wild animal species in the 1890s. The result was widespread starvation—reports from Tanzania alone suggest that more than 60 percent of Maasai people died—the collapse of existing economic institutions, and long-term ecological changes associated with the loss of grazing animals. Transmission of chikungunya virus and Zika virus, two pathogens that are transmitted to people by mosquitoes, have recently been documented for the first time in the Western Hemisphere. Although pathogen emergence is not new, it remains a fascinating and terrifying topic. Recent emergence events have led to a wealth of books on the subject.