Amoebae, unicellular organisms, can play a key role in the survival and spread of deadly plague bacteria.
The plague bacterium survives, thrives, and replicates when ingested by an amoeba. This discovery could help scientists understand why plague outbreaks can smolder and reappear suddenly.
The plague - the most famous dating back to XIV century - persists today. It is experiencing a resurgence, mainly in sub-Saharan Africa. Elsewhere, as in Colorado, animals carry fleas that harbor the bacteria. Outbreaks can wipe out whole colonies of prairie dogs and infect humans like pets. Omnipresent in soil and water, amoebae can be ideal hosts for plague bacteria as they infiltrate the soil.
The amoeba: the ideal host
To test the theory, Dr. Markman and his teammates donned protective suits and took soil samples near the outbreaks of plague. The researchers isolated different amoeba species and tested whether the bacteria survived ingestion by the different amoebae. In the laboratory, the plague bacteria lived up to 48 hours inside the amoeba. "The bacteria were not only dragging, they survived inside the amoebae while breeding. " describes Dr. Markman.
The next step for the scientists is to explore the survival time of the plague in amoebae, as well as the risk that the latter will resuscitate plague bacteria years later.