The plague. It's not just a disease of the past.

This highly contagious killer is striking again across the globe. Nearly 3,000 people caught the plague last year, and hundreds have died. It's an ugly and painful death "“ if you're really curious and really brave, here are the some examples via Google Images.

Just days ago the WHO (not that "The Who," the World Heath Organization) issued a warning, pointing out that precautions need to be taken in case the plague is used as a biological weapon. If an attack like that happened, it most certainly wouldn't be the first time the plague has been used as a weapon of war. For the last 700 years, the practice has been more common that you might think.

The Corpses of Caffa

In 1346, The Tartar Army was doing its best to capture Caffa, a walled city on the Black Sea in present-day Ukraine. They weren't having much luck, especially after an outbreak of the plague started killing them off. So in what can only be called a strange bit of inspiration (and one of the first instances of biological warfare), the Tartars gathered up the plague-infected corpses and catapulted them over the city walls, using the flying bodies to spread the disease. After the plague started killing off the city's inhabitants, the Tartars easily took Caffa. But although they may have won the battle, the Tartars really lost the war. The newly infected fled the city of Caffa to Italy, spreading the plague everywhere they went, effectively starting the outbreak of Black Death that would kill off much of Europe. [Image courtesy of StupidBeaver.com.]

Unit 731



During the Second World War, Unit 731 "“ a secret unit of the Japanese army "“ was created for the sole purpose of turning illnesses into weapons of mass infection. Masterminded by General Shiro Ishii, this unit conducted horrible experiments on humans, including vivisections without anesthesia (ouch) and unnecessary amputations. General Ishii was especially fascinated by the plague and numerous possibilities it held as a weapon of war, but testing proved difficult. Japanese scientists tried spreading the plague to unsuspecting victims via the water system and through aerosol, but nothing worked. Until, that is, they went back to the basics of the disease.

Someone came up with the idea of using the animal behind the original spread of the plague: the flea. Ceramic bombs filled with infected fleas were dropped on several unsuspecting cities in China (where in a sad twist of fate, the bubonic plague is said to have originally started before making its way to Europe and the rest of the world). The resulting epidemic killed thousands. In all, Unit 731 would be responsible for the deaths of nearly half a million people. [Image courtesy of BU.edu.]

The Cold War Race to the Plague "“ USSR



During the Cold War, the Soviet Union ramped up its efforts to find a use for diseases like the plague. This was nothing new, as they had been stockpiling battle-ready bio-terror weapons for decades. During the mid to late 20th century, the Soviet scientists not only came up with a new strain of the plague that was resistant to both vaccines and antibiotics, they found a way to mass produce it. Former Soviet officials say they had 1,500 metric tons of plague ready at all times for use in their intercontinental ballistic missiles. At all times! Soviet research on bio-terror weapons continued well into the 1990s before being shut down by the government. No word on what they did with the stockpile of plague, but in theory, it should all be dead by now. In theory.

The Cold War Race to the Plague "“ USA



The Soviets weren't alone in their race to weaponize the plague. For decades, the United States tried to create a plague bomb (and a gay bomb, among other things). Their efforts were decidedly less successful than the Soviets. Scientists said they had numerous problems with production and were unable to overcome the challenge of controlling the disease once it had been created. The U.S. is said to have ceased production of the plague and shut down its offensive biological weapons research during the 1970s.

Holding Tucson Hostage



In September of 1978, Tucson, Arizona, Mayor Lewis Murphy started getting threatening letters. Unless demands were met, the sender warned, he would release bubonic plague-carrying fleas on the hapless city. Among the demands was a $500,000 dollar ransom, food for the poor, and for a local hospital to resume performing abortions. The threat of the plague was enough for Mayor Murphy, because he sent the police to deliver the money. But when they arrived at the delivery site, no one showed up. The sender of the letters is still unknown.

* * * * *

If all these attempts at weaponizing the plague aren't enough to keep you up at night, then how about this: In 1995, a man in Ohio with "suspect" motives was able to buy plague bacilli using fraudulent means through the mail. In the southwestern U.S., there are reports of extremist groups capturing plague-carrying animals. You might be perfectly healthy now. But just remember, someone out there has the plague, and wants you to catch it.

Stefanie Fontanez is an occasional contributor to mentalfloss.com. She won't always be this scary.