Plague in Mongolia! Plague in Colorado! Should We Be Worried?

Photo by conor rabbett on Unsplash

Uh oh. We appear to have an outbreak of plague in Mongolia. Last thing we need, right?

Oh, and it’s been found in squirrels in Colorado. Eep! Scary!

Let’s unpack this and work out whether we really need to be worried.

What Causes the Black Plague?

The “actual” plague, which comes in bubonic, septicemic and pneumonic variations is caused by a bacteria called Yersinia pestis.

This bacteria is, like COVID-19, essentially zoonotic. It’s endemic in multiple species of rodent and is transmitted primarily by infected fleas (both rodent fleas who accidentally bite humans and potentially human fleas who accidentally bite rodents). It can also sometimes be found in rabbits and in carnivores that eat affected animals. This includes cats, making it yet another reason not to let kitty outdoors. In fact, cats are particularly susceptible and can then sometimes pass it to their owner. Dogs and cats can both bring infected fleas into the home.

Generally, it starts off as bubonic plague, which infects the lymphatic system. Septicemic (blood) and pneumonic (lung) variants occur if it’s not treated promptly.

Although it can spread between people in close contact, this is rare and has not…