I learned in school that in the 14. century the “Black Death” plague was caused by the bacterium Yersinia pestis which was transmitted by rat fleas. However, this may not be true. So yes, plague is caused by Yersinia pestis, but there are different infection ways: (I) from rat fleas to human, (II) from human ectoparasites (fleas and lice) to human and (III) from human to human by inhalation from infected droplets. But how you can find out many centuries later which infection way was the basis for the “Black Death”? The answer is: with mathematical models! Katharine R. Dean, et al. (PNAS 2018) created mathematical models for all three infection ways. So they were able to simulate how infection rates would develop over time for each type of infection. Then they fitted the simulation results to real outbreak data and showed that in many cases the “human ectoparasites to human” model fits best. Of course, it can still be that it was a mixture of different infection ways and that the main infection way differed from region to region. Nevertheless, it shows that the story which we learn in school, that the plague is caused by infected rats and rat fleas, is maybe too easy.
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IdeaI love to increase my general science knowledge by reading papers from different fields of science. Here I share some of them. Archiv
März 2018
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