2020 has been wild already as we struggle with a world pandemic. There are roughly 50-60 cases of bubonic plague a year worldwide and a dozen or so are usually in the Southwest part of the United States. This is part of the “plague happens” motto Aislinn Cain uses in D&R from time to time. However, they aren’t usually clusters. Which is why the 3 cases in Mongolia made international news.
The three cases are scary because they happened in less than a week. In Russia and Mongolia, it’s not uncommon. A prairie dog like rodent called a marmot is among the most common plague host around. What most people know about plague is that it passes from rats to fleas and the fleas flee the dead bodies of the rats and move to other hosts such as household pets and eventually people.
However, while that is a common transmission source, it’s definitely not the only transmission source. Especially since the Southwest US doesn’t have marmots. All rodents can carry bubonic plague. In the US it’s usually prairie dogs, in Mongolia, it’s the poor marmot. And in eastern Russia, China, and Mongolia marmot is a food source for indigenous people. Eating marmot infected with bubonic plague is a fairly common transmission source as a result and accounts for something like half the plague cases in the world.
Three cases in a week is worrisome because we have to wonder if plague infection rates of marmots is on the rise. In 2018 for example there were only 18 cases of plague in all of Russia, China, and Mongolia, a further 7 cases in the US and another 33 in Africa. For a total of 58 cases which means roughly 5 cases a month for all of 2018 with the majority happening in the conflict regions of Africa. Drought, famine, and conflict encourage the eating of animals not normally consumed by starving populations as well as further encouraging closer habitation between plague infected animals and humans. In 2019, there were only 47 cases of plague worldwide for an average of less than 4 cases a month and again, most of the cases were in Africa.
Luckily, unlike the 1300s, we have antibiotics and if caught early, plague can be treated and cured with antibiotics and it is not communicable person to person. If not caught early, it has a 30-40% mortality rate. But that’s normal plague Yersinia Pestis. Throughout human history a few serious mutations of Y. Pestis has occurred and we’ve found evidence of this in plague pits in Europe, the Middle East, and a few other places. Sometimes, when Y. Pestis mutates it gets big, bad, and unstoppable. We know for sure that the Y. Pestis also known as the Justinian Plague, was communicable in bodily fluids. It killed millions and was named after the Emperor Justinian who ruled when it hit. It is one of the great population bottlenecks and the first caused by Bubonic Plague; killing an estimated 25 million to 100 million people in Europe and the Middle East. It is one of the contributing factors in the collapse of the Roman Empire which was very hard hit by it. Then came the 14th century… There is still a ton of debate about the Y. Pestis that decimated Europe, Asia, and Africa in the 1300s. It killed at least 50 million people across the three continents and produced the second great population bottleneck, it’s possible that nearly half the population of the continents listed died during the 7(or so) years of the Black Death. We know for sure it traveled east to west, coming out of Mongolia, Russia, and China and moving into Europe and Africa. Carried by rat fleas is the most questionable part. It spread like wildlife, way faster than flea and flea infestations could have spread it. Like Justinian Plague, it probably became communicable person to person possibly in the form of Bubonic Pneumonia, and the mortality rate seems to have been higher with Black Death than Justinian Plague or even regular plague.
What does all that matter? Well, if the plague infection in marmots is increasing, we will begin to see higher rates of infection in humans. There are three main forms of Bubonic Plague; Bubonic (it infects the lymph nodes), Septicemic (in this form it enters the bloodstream and can act like hemorrhagic fever causing people to bleed to death both internally and externally), and Pneumonic (this is the most dangerous form and has a higher mortality rate than the first two; it causes respiratory shock and failure). It’s unlikely plague will reach pandemic proportions, but 2020 has been weird.