While we understand the plague, we understand how it is transferred, how it works, what we do not fully understand is how plague recurs after lying dormant.

Findings published in the journal emerging infectious diseases, suggest that the bacteria that causes plague could be lying dormant in common soil and water sources. Which would explain why plague suddenly re-emerges without warning in countries such as Madagascar and the United States. In Madagascar last year a violent outbreak left 202 people dead.

David Markman from Colorado State University who led the study notes that the origins of sporadic outbreaks of plague in many different parts of the world are still not well understood. One of the reasons there are so many unanswered questions is that the plague is present in so many different environments, from the desert to the jungle, making it difficult to find a singular mechanism to unite the different locations to explain when, where and why we have outbreaks.

David Markman’s team theorise that It could be due to amoebae, bugs which could be the culprits protecting the plague pathogens in the soil. Testing five species of amoebae with plague bacteria to see their reaction using a genetically altered strain of plague which glows bright green, they observed the amoebae ingesting the plague, with the pathogens alive and replicating well inside the amoebae.

Their research does not mean that this process occurs naturally, but it is an important theory getting us one step closer.