Rats had a bad press: Black death was really caused by giant gerbils
But history may have to be tweaked after academics suggested giant gerbils in Asia may have been the source of repeated outbreaks of the Black Death.
The study found that epidemics of the plague were triggered by fluctuations in climate, with peaks in Europe coming after periods of warm weather in central Asia when gerbil populations, which carried the bacterium Yersinia pestis, that caused the plague, boomed.
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Hide AdThe Black Death originated in Asia and arrived in the ports of the Mediterranean in 1347, marking the start of “the second plague pandemic”, which lasted in Europe until the early 19th century, killing millions.
Scientists propose that instead of being introduced once to Europe and surviving in local wildlife and rodent populations, the plague was in fact brought in many times over a period of more than 400 years.
The study, published in the Proceedings of the National Academy of Sciences, saw researchers analyse more than 7,700 documented outbreaks of plague in Europe with tree-ring records from there and Asia.
While climate conditions in Europe were not optimal for the development of plague, when it warmed in Asia, plague appeared in Europe around 15 years later.
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Hide AdThe study does not let the rat off the hook as a disease carrier, saying they probably played a role maintaining plague outbreaks on ships and importing it into harbours, but say its role “as a potential plague reservoir is rather questionable.”
But it says when plague-infected rodent populations collapsed in central Asia, when weather conditions changed, the fleas they carried were forced to find alternative hosts.
They suggest with trade between East and West becoming ever-more prevalent, the disease came into Europe in the caravans of merchants and traders.
The report’s co-author Professor Nils Christian Stenseth, from the University of Oslo, said if they were correct history may have to be rewritten: “Wherever there were good conditions for gerbils and fleas in central Asia, some years later the bacteria shows up in harbour cities in Europe and then spreads across the continent. “We originally thought (waves of plagues) was due to rats and climatic changes in Europe, but now we know it goes back to Central Asia.”
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Hide AdThe Black Death reached York in the spring of 1349, returning in 1361, 1369, 1375, 1378 and 1390. Poll tax returns showed that after the Black Death the city’s population of 15,000 dropped to around 10,000.
During times of plague in the 16th and 17th centuries, victims were brought from the city and housed in wooden lodges on Hob Moor where there are two stones, one called the Plague Stone, reputedly where the sick would pay for food which had been bought for them by placing money in water or vinegar in the central hollow.
Their fleas may have reached our shores by other means - but it seems unlikely the gerbils did. York City archeologist John Oxley said there was plenty of evidence in the records of rats - but none for gerbils.
He said: “There’s no mention that I can find in a rapid trawl of the records of gerbils - but rats were really quite common, we find them in the Viking, Roman and mediaeval context. There’s evidence for them being in the urban environment, grawing on bones that have been thrown into pits. There is a clearly a large rat population in places like York.”