The Bubonic Plague has for centuries been relegated to the grimmest annals of the history books, one of humankind's gorier chapters and often said to be the grisly muse for the children’s nursery rhyme, “Ring Around the Rosie” (though this is of questionable veracity).
Whatever the case, most people would be surprised to discover that the bacteria responsible for what has come to be known as the Black Death, or simply plague, is still around today.
According to the CDC’s webpage, the World Health Organization reports between 1,000 and 3,000 cases of plague each year, most commonly in the western and southwestern parts of the United States, as well as South America, Africa and Asia.
Because plague is so much less virulent today – with slighter symptoms and without the killer capacity for transmission it possessed in the late 1340s – researchers have wondered if perhaps the medieval version is different from that which we now see. That, however, does not appear to be the case.
By extracting DNA from teeth found in London plague victims, they were able to extract about 99 percent of the bacteria’s genome, reports Elizabeth Weise in her article “Researchers trace the roots of Europe's Black Death plague.” While the genome is not fully complete, it is enough to establish that the plague of yester-century wasn’t much more virulent than today’s strain.
From this, researchers have theorized that perhaps the Black Death’s unbelievably massive fatality rates resulted not from the plague’s virulence but from a cooler climate, which led to malnourishment and poor immunity.
The parallels with today, while remote, are not ruled out. Climate change is always a factor where human health is concerned. Like all animals, we need time to adapt to variations in food supply, temperature, disease and weather. The Black Death may not, after all, be the story of an unconquerable killer but rather the timely lesson of a society ill-prepared to deal with a massive population and a moderate threat.