Tornadoes, hurricanes, earthquakes, mass extinctions from giant meteorite collisions -- and epidemics. I remember first reading Daniel Defoe's A Journal of the Plague Year, about an outbreak of the Black Death in London in 1664 and 1665, when I was in college, and being simultaneously horrified and mesmerized at the scale of it. An estimated 100,000 people died in two years -- a quarter of London's population.
But even that is dwarfed by two other epidemics. First, there's the infamous outbreak of bubonic plague that started in 1347 and, by some estimates, killed one-third of the human population of the Earth -- something on the order of fifty million people. The worst, though, was the "Spanish flu" epidemic of 1918 and 1919. Odd that an event only a hundred years ago, and that killed an estimated 75 million people worldwide -- twice as many as World War I, which was happening at the same time -- is much less known. Mention the Black Death, and almost everyone has an idea of what it is; mention the Spanish flu, and often all you get is a puzzled look.
Danse Macabre by Michael Wolgemut [image is in the Public Domain]
The origin of Yersinia pestis and the early stages of its evolution are fundamental subjects of investigation given its high virulence and mortality that resulted from past pandemics. Although the earliest evidence of Y. pestis infections in humans has been identified in Late Neolithic/Bronze Age Eurasia (LNBA 5000–3500y BP), these strains lack key genetic components required for flea adaptation, thus making their mode of transmission and disease presentation in humans unclear. Here, we reconstruct ancient Y. pestis genomes from individuals associated with the Late Bronze Age period (~3800 BP) in the Samara region of modern-day Russia. We show clear distinctions between our new strains and the LNBA lineage, and suggest that the full ability for flea-mediated transmission causing bubonic plague evolved more than 1000 years earlier than previously suggested. Finally, we propose that several Y. pestis lineages were established during the Bronze Age, some of which persist to the present day.Which is fascinating enough, but it bears mention that there are still a number of epidemics that scientists have no clear explanation for. Here are three of the most puzzling:
- "Sweating sickness." In the late 15th and early 16th centuries, several waves of contagious illness swept through western Europe. It killed fast -- starting with disorientation, fever, chills, aching joints, and finally progressing to delirium and copious sweating. Most of the victims died within 36 hours of the onset. It claimed a number of well-known victims, including Prince Arthur of England -- the son of King Henry VII, and brother of King Henry VIII. Arthur's death at the age of fifteen put Henry in line for the throne, and set into motion events that would change the world -- such as the English Reformation and the founding of the Anglican Church. Sweating sickness went as quickly as it started -- the last outbreak was in 1551, and it hasn't been seen since. Scientists are still mystified as to the cause, but the speculation is it might have been a hantavirus, carried by mice.
- The Dancing Plague of 1518. In eastern France and western Germany, people were stricken by a disorder that caused shaking, mania, and... a desperation to dance. People took to the streets, dancing desperately, many of them until they died of hunger, exposure, heat exhaustion, or stroke. In Strasbourg alone, at the height of the plague, it was killing fifteen people a day. It, like the sweating sickness, vanished as soon as it appeared, leaving everyone mystified as to its cause -- although some researchers suspect it might have been caused by ergot, a fungus that grows on wheat and rye and produces lysergic acid diethylamide -- LSD.
- "Nodding syndrome." This one is much more recent, having first emerged in the 1960s in Sudan. It affects children, causing listlessness, stunting of growth (especially of the brain), and a peculiar symptom called a "nodding seizure," often triggered by eating or becoming cold. The child's head bobs, and (s)he becomes unresponsive, the seizures lasting for up to ten or fifteen minutes. It's progressive and fatal -- the usual duration being about three years. To this day no one knows the cause, although some suspect it might be connected to parasitism by the roundworm Onchocercus volvulus, which is endemic in the area and also causes "river blindness."
Anyhow, I realize this is all kind of morbid, and I have no desire to ruin your mood. After all, we live in an age where most of the worst diseases of antiquity have been vanished; even bubonic plague, if it's caught quickly, can be cured with antibiotics (and yes, there are still cases of it today). Thankfully, we seem to have gotten rid of sweating sickness and the dancing plague, even if we've replaced them with Ebola fever and chikungunya and West Nile virus. I'll still take what we've got today over life in the past, which was (accurately) described by Thomas Hobbes as "solitary, nasty, poor, brutish, and short."
Have a nice day.
This week's recommended read is Wait, What? And Life's Other Essential Questions by James E. Ryan. Ryan frames the whole of critical thinking in a fascinating way. He says we can avoid most of the pitfalls in logic by asking five questions: "What?" "I wonder..." "Couldn't we at least...?" "How can I help?" and "What truly matters?" Along the way, he considers examples from history, politics, and science, and encourages you to think about the deep issues -- and not to take anything for granted.