Yes, you can still get the bubonic plague. Here's what to look out for
“Bubonic” is almost onomatopoeic. It sounds bulbous and grotesque and ancient. It sounds like something your great great grandmother might have contracted as a child, along with “the consumption.” So when headlines proclaim that the bubonic plague is alive in Arizona (or New Mexico, or wherever) it feels like some archaic monster has risen from the grave.
The reality is that it never actually died.
Bubonic plague lives on
The plague has infected at least a handful of people in the U.S. every year for as long as the country has been around. The number varies from just one to 17 annually. And every few years, one of those cases proves fatal. That might sound creepy—come on, it's the plague we're talking about here—but let's take a minute to appreciate how great we are at fighting it off, relatively speaking. This is a disease that wiped out around 100 million people in the 14th century. That was half the population of Europe and a third of the Middle East. But since 1900, the U.S. has seen just over 1,000 cases total.
Most of those infections happen in the southwest, with a smattering of others spread across the west coast and up towards Montana. You might think of the plague as spreading rapidly from person to person, but the bubonic plague actually only spreads through blood. That's the most common type of the plague. The other two, septicemic and pneumonic, happen when Yersinia pestis bacteria spread out into further reaches of the body. Pneumonic plague—where the bacteria has reached the lungs—is the only form of plague that can spread easily from person to person. Otherwise it takes some very intimate contact to catch. From human to human, anyway.
The bubonic plague spreads through a much tinier vector: the flea. Plague bacteria can live inside adorable rodents like squirrels and prairie dogs without killing them. When fleas bite these little guys, the fleas become carriers of the bacteria. Fleas in turn bite humans, infecting them. And if there's one thing you can say about the midwest, it's that they've got a lot of little rodents—especially in rural areas. That's why those areas remain a (relative) hotbed for the plague, and why you should avoid getting near any sweet prairie pups.
Incidentally, it's also why Pope Clement VI was able to keep himself free and clear of the disease by sitting between two fires. At the time he had no idea why it worked—people had no concept of bacteria or viruses—but he was unknowingly preventing small critters and fleas from coming near him.
Even if you do get the plague, you'll (probably) be okay
The good news is that we've cut the mortality rate for the plague by a lot. The disease used to kill around half of its victims, but since the advent of modern antibiotics we've reduced that to about 10 percent. The odds are even better if you can get the meds within 24 hours of your first symptoms. Delays in treatment give the bacteria more time to spread and cause bubonic bulges.
The word “bubonic” refers to the swollen lymph nodes in the armpit and groin that patients get from the bacteria. The bulges are called “buboes,” and they're gross—but they're not the worst thing about the plague. The worst thing is the gangrene.
Gangrene is another vaguely onomatopoeic word that means “flesh that dies when it can't receive blood and then starts oozing foul-smelling pus and decaying right there on your body, egads.” Gangrene can happen almost anywhere on the body, but the plague tends to produce it at the extremities (and also—horrifyingly—on the lips and the tip of the nose). If that doesn't deter you from trying to pet squirrels in rural New Mexico, nothing will.
Fortunately, modern antibiotics are quite effective at killing the bacteria, especially if taken early. And unlike ancient days when plague victims were basically left for dead, many of the symptoms can be managed and mitigated today.
To avoid the plague, avoid the lil critters who carry it
Given how rare the plague is, this really shouldn't be a huge concern. But if for those who happen to live in the southwest (or are just visiting), here are a few tips: The first is to stop trying to get near cute rodents. It's just not worth it. Pet someone's dog instead. The second is to use insect repellant, specifically one that has DEET in it. Despite its controversies, DEET is great at keeping fleas at bay (just try not to spray it all over the place). And lastly, don't touch dead animals with your bare hands. If a squirrel dies in your yard, use a shovel to move it away.
If you're worried that you might have the plague, go see a doctor. Right now. A lot of the symptoms, like fever and muscle aches, can seem like a general virus. But those buboes cannot be mistaken. The signs will appear suddenly a couple days after exposure, and the plague usually kills within 10 days (if it's going to kill at all). Now is not the time to suffer in dramatic silence. Take those buboes seriously.
Sara Chodosh, Popular Science