How the flea spreads the BLACK PEST

Normally the flea bites simply cause slight discomfort in the form of rashes due to the allergy that most humans have to their saliva, however, the bite It is potentially dangerous since the flea can transmit a series of diseases such as typhus or one of the most terrible pandemics in history: Black Death .In Science Daily Online we have investigated to find out c how the flea spreads the BLACK PEST.

How the flea spreads the BLACK PEST

Black plague is caused by a bacterium called Yersinia pestis .We currently know that passes from rodents , especially the black rat or rattus rattus , to human beings .Black rats were very common in houses, mills or barns for many times in the history of mankind.Between one mammal and another, the responsible for carrying the bacteria is the flea .It must be borne in mind that, in some cases, it is also transmitted from human to human in the same way: the flea.

The fleas to reproduce need the blood of the mammals that bite and then lay their eggs.By chopping an infected rodent with yersinia pestis, the bacteria enters and remains deposited in the stomach of the flea.After this, in a process that lasts approximately fourteen days, blocks the stomach of your guest.When the flea tries to feed it fails to do so due to this blockage and after several attempts to bite and feed, regurgitates the stomach contents in the bloodstream of his guest.This is infected.When yersinia pestis is installed in the flea's stomach, it needs a temperature that is below 27'5 ° C to spread .When these conditions occur, the bacteria releases an enzyme that accelerates the expansion in the stomach of the host.The cool temperatures favor the expansion of the disease.The climatic changes suffered in Europe for centuries seem to coincide with the expansion of the disease.The first pandemic, in the sixth century, coincides with a Climate change that particularly affected North Africa, and the beginning of the second, in the fourteenth century, does so with the so-called Little Ice Age that affected Europe from that century to the nineteenth.

How the flea spreads the BLACK PEST

Pieter Bruegel (1562) The triumph of death

All mammals in general can get this disease , but most rodents, cats and humans are more likely to do so than others, such as dogs, which are much more resistant to it .The plague has three variants ; the primary one, to which it was possible to survive, in which the lymph nodes swell and therefore it is called bubonica , the septicemic , in which the disease was concentrated in the blood and produced dark spots all over the body (hence the name black plague) and the last one, the pneumonia plague, which caused coughs and expectorations to affect the respiratory tract place to spread among humans through the air.No one survives these last two variants.

If you have been interested in this post, you may want to know what hygiene was like in the Middle Ages.

Cover image: Louis Duveau: La peste d'Elliant (1849, musee des beaux-arts de Quimper).

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