'Gerbils replace rats' as main cause of Black Death

Black rats may not have been to blame for numerous outbreaks of the bubonic plague across Europe, a study suggests.

Scientists believe repeat epidemics of the Black Death, which arrived in Europe in the mid-14th Century, instead trace back to gerbils from Asia. The study is in the Proceedings of the National Academy of Sciences.

It had been thought that black rats were responsible for allowing the plague to establish in Europe, with new outbreaks occurring when fleas jumped from infected rodents to humans.

However, Prof Stenseth and his colleagues do not think a rat reservoir was to blame. They compared tree-ring records from Europe with 7,711 historical plague outbreaks to see if the weather conditions would have been optimum for a rat-driven outbreak.

Instead, the team believes that specific weather conditions in Asia may have caused another plague-carrying rodent - the giant gerbil - to thrive. And this then later led to epidemics in Europe.

The fleas, which also do well in these conditions, would then jump to domestic animals or to humans. And because this was a period when trade between the East and West was at a peak, the plague was most likely brought to Europe along the silk road.

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