It may not surprise you to learn that natural disasters greatly intrigue me.

I own books about the Krakatoa volcanic explosion of 1883, the Johnstown Flood of 1889, and the Galveston Hurricane of 1900. My “purchased but un-read” shelf holds a book about the San Francisco earthquake of 1906. Give me a disaster, and enough time, and I’ll research it.

(I also have books about the sinkings of the Titanic, the Lusitania, and the USS Indianapolis. And the Mount Everest disaster of 1996. And a variety of famous crimes. But I’m not macabre, honestly.)

As it happens, I started writing this post last week, a few days before I (ironically) came down with the nastiest case of stomach flu I’ve ever had, from which I’m still recovering. I am assuming that I did not give myself bad flu juju with all the researching.

Anyway, I recently read a novel that incorporated the events of the real-life 1918 influenza pandemic. (The novel wasn’t that great, so I’ll spare you the title.) In a note about the book, the author wrote that, for some reason, many people know very little about the 1918 flu. Either it isn’t taught in school, or it’s glossed over. I certainly don’t remember learning about it.

Which is strange, because that flu has been called “the worst medical holocaust in history.” Its only possible rival is the European Black Death of the mid-14th-century. I’ll get to the statistics in a moment.

The Great Flu occurred at the end of World War I, which may have something to do with its step-sister status in history courses. The war, of course, was also responsible for much of the disease’s spread, as soldiers carried it into barracks and foxholes, and as information about the virus was suppressed by wartime censorship. In fact, the flu was first (and erroneously) known as the “Spanish Flu,” because that country was one of the few that did not censor news of the illness.

How deadly was it? In its first 25 weeks, the flu may have killed 25 million people.

Just sit with that for a minute. A million souls a week. That’s the equivalent of having more than four of the horrifying 2004 Tsunamis a week – for six months solid.

And after that, things got significantly worse.

Six months into the ordeal, the flu’s second wave hit, and it once again swept around the world – only this time, it was even deadlier. The pandemic showed no mercy, in any quarter. Here are some more figures: 17 million dead in India. More than 400,000 dead in France. More than a half million dead in the United States. Small island communities were particularly hard hit: 1.5 million dead in Indonesia; 14% of the population dead in Tahiti; 20% in Samoa. Whole villages dead in Alaska.

It is difficult to grasp the reality of numbers, when they get that high, but it’s also difficult to imagine the sheer terror, the panic of those long months, when friends and neighbors and family members were dropping all around, and no one knew what had caused the sickness, or how to fight it; when medical care was still primitive and the discovery of antibiotics was still ten years away.

Eventually, a third of the world’s entire population was infected with the disease. And by the exhausting end of it, in 1921, somewhere between 50 million and 100 million people had died from it.

Well, but that wasn’t quite the end of it.

Because in 2005, government scientists brought the 1918 influenza back to life, using tissue samples recovered from a victim who had been buried (and thus preserved) in the Alaskan tundra. The flu’s complete genome sequence was published that year in an article in Nature magazine. (The resurrected virus was still powerful enough to kill lab monkeys that were injected with it.)

Researchers were finally able to determine what caused the virus and why it killed so thoroughly. First of all, this most deadly of pathogens came from an avian source.

In other words, yes, it was a bird flu.

The striking difference between this and other illnesses (other than its enormous mortality rate) had been that the 1918 flu mostly killed young, healthy adults. In 2005, researchers were able to determine that the virus caused an overreaction of immune systems (a “cytokine storm”), so people with the strongest immune systems had been the worst hit.

In 2008, more studies suggested that what actually killed most of the victims may have been the secondary bacterial pneumonia that set up in the victim’s weakened lungs, and not the virus itself. That same year, researchers found that childhood survivors of the flu, who were now in their 90’s, still had antibodies to the 1918 flu in their blood. These antibodies, when extracted, were strong enough to protect lab mice from the original flu virus.

It’s puzzling that such an important biological event has been skimmed over, in the annals of history – an event that was so potent, it’s still providing answers to itself, nearly 100 years later.

It doesn’t get much more significant than that.

Oh, and my flu (can I still call it that, after all this?)…well, I’m recovering, slowly but nicely. Thank God for fully-stocked drugstores. And husbands to fetch things from them.