How Plague Bacteria Could Be Hiding Everywhere Around Us

Certain conditions provide plague bacteria a place to replicate and bide their time before conditions are right for another outbreak to occur.
Plague is a highly contagious disease that has killed millions of people over the past 1,400 years. Outbreaks still sporadically occur in as many as 36 countries worldwide. Perhaps one of the greatest remaining mysteries surrounding plague is how and where it survives between outbreaks.

 

Like many other pathogens, the bacteria that causes plague, Yersinia pestis, cannot survive for long periods of time in the environment without protection. Despite this, plague outbreaks continually recur in many locations. This suggests that the bacteria are able to find refuge and survive for several years after an outbreak before reappearing, seemingly out of nowhere, and starting another infection cycle. Understanding where they hide and how they survive and reappear is extremely important for preventing future outbreaks.

Our 2018 study conducted at Colorado State University’s Infectious Disease Research Center shows that amoebae – common soil and waterborne microorganisms that eat bacteria – could play a role in protecting this dangerous pathogen between outbreaks. This relationship may give plague bacteria a place to replicate and bide their time before conditions are right for another outbreak to occur.

An ancient and mysterious killer

Plague has caused three deadly worldwide pandemics. The Plague of Justinian killed millions of people in the Byzantine Empire between the years 541 and 750. Next, the notorious Black Death ravaged much of Asia and Europe from 1330 to 1480, killing approximately 30 percent of all Europeans. Most recently, plague reappeared in China in 1855 and spread to ports worldwide over the following century, killing some 12 million people. Thousands of small outbreaks have occurred between and following these events.