A pair of researchers with NIH has discovered the evolutionary path that a bacterium that causes the plague took to allow for transmission via fleas. In their paper published in Proceedings of the National Academy of Sciences, Iman Chouikha and Joseph Hinnebusch describe how they studied the bacterium and its genes to learn how it adapted to become less lethal to fleas and thus better able to infect more hosts.
The plague, as most are aware, has a deadly history—it’s killed millions of people over time and still today evokes fear when mentioned. Scientists have known for some time that the reason it was so deadly was because of the easy transmission route, from fleas to rodents and humans. But fleas, it turns out, weren’t always such great carriers, the researchers with this new effort learned. In fact, the bacteria had to evolve to be less harmful to fleas so that they could be better carriers.
The research pair actually studied two types of bacteria, Yersinia pseudotuberculosisand Yersinia pestis. The former is relatively harmless in that it’s not a good carrier of plague. The later is the real culprit.
Read more at: Phys.org