TheBlack Deathis arguably one of the most evocative events in human chronicle : the mere quotation of this plague conspire up images of far-flung destruction and the adamantine bed covering of disease . Indeed , approximation of the human toll of the seven - year - long fourteenth - C epidemic range from 75 to 200 million destruction . The bacterium responsible for , Yersinia plague , has undergone organic evolution as every other being on Earth has , and a new study published in theJournal of Medical Entomologyhas revealed details of its likely ancient ancestor .
A unmarried flea , roughly 20 million years ago , managed to get itself snare in gold , conserve with it several examples of bacteria . Although the bacterium can not be extracted from the gold and subjected to genetic testing to substantiate its evolutionary link to modern dayY. plague , the investigator , led by entomologistDr George Poinar , Jr. , notice several similarities . Firstly , the bacteria were attached to the proboscis ( feeding organ ) and rectum of the flea – two areas the contemporary equivalent is often observe . Secondly , their physical characteristic , including their size and shape , nearly resemble that of the modernY. pestilence . Lastly , they are both the same character of bacterium : coccobacillus .
If it turn out the bacteria are indeed transmissible to the contemporary bubonic plague , then remarkably this would mean that they forego the egress ofHomo sapiens – our own species – by at least 19 million years . Although the strain of bacterium infect modern humans may have only evolve around 20,000 twelvemonth ago , far more ancient strains of the pathogen could have develop to exist within other animate being , including gnawer – the creatures originally thought to have brought the plague to the shores of Europe in the 14thcentury .
The flea itself is one of very few preserve in gold and has thus undergo very modified biological degradation . Consequently , not only are the ancient bacterium preserved within the amber prison of the flea , but their method of infection from host to server is also possibly preserved .
After feeding off a infestation - infected beast , Y. pestisforms a sticky mass within part of the flea ’s stomach , the proventriculus . This occlusion reduces the catamenia of sucked - up origin into the flea ’s breadbasket , and they oppose by find another animate being to feed on . As their trunk is insert into another animal , the bacterial colony is often evacuated into the new master of ceremonies ’s circulatory organization . The dried droplets found at the tip of the fossilized ancient flea ’s proboscis could indeed be the same sticky bacterial mess .
Although no humans were around 20 million year ago to be infect by this potentialY. pestisrelative , there were plenty of other ancient organisms around . The amber - encapsulated flea specimen was find in a mine within the Dominican Republic , which millions of age ago was a tropical , moist forest home plate to gnawer , birds and reptile . If an ancient ancestor ofY. pestisdid exist within this 20 million - twelvemonth - former ecosystem , then it may have played a gravid role in work it than antecedently thought , driving the extinctionof specific coinage .
Withfour casesof the human plague diagnosed in the United States this class , the vaporous longevity of the group of bacteria responsible is clean to see ; an evolutionary offshoot of death , tenner of gazillion of years in the making .
