The Eternal Return of the Plague
The plague conjures up images of the medieval Black Death, and perhaps the vaguely reassuring sense that, in the developed world, such dangers are a scourge of the past. But, as the recent outbreak in Madagascar makes clear, the upper hand humans have over the plague today is tenuous and almost certainly transient.
NORMAN, OKLAHOMA – “Fearsome Plague Epidemic Strikes Madagascar.” That recent New York Times headline might sound like the synopsis of a horror movie. The epidemic gripping Madagascar is not just any plague, and it certainly isn’t some Hollywood apocalypse. It’s the plague, caused by the bacterium Yersinia pestis, agent of the notorious bubonic plague.
For most people, “the plague” conjures up images of the medieval Black Death, and perhaps a vaguely reassuring sense that, in the developed world, such ancient dangers are long past. But in recent years, thanks to the work of geneticists, archaeologists, and historians, we now know that human civilization and the plague have a much deeper and more intimate association than previously assumed. Lessons learned from studying this historic interaction could reshape how we think about global public health today.
All infectious diseases are caused by pathogens – bacteria, viruses, protozoa, and parasites – that are capable of subverting our immune systems long enough to make us sick. These organisms are the product of their own biological evolution, and the history of the plague’s development is perhaps (along with maybe HIV) the most detailed biography of any pathogen known to science.