Past pandemics that ravaged Europe

In 430BC, during the Peloponnesian war against their great rival Sparta, the people of Athens were hit by a deadly disease that has defied diagnosis to this day. By the end of the plague Athens had lost a third of its army. The Greek historian Thucydides survived a bout of this unknown killer and left a vivid account of its symptoms, which make for frightening reading.

"People in good health were all of a sudden attacked by violent heats in the head, and redness and inflammation in the eyes, the inward parts, such as the throat or tongue, becoming bloody and emitting an unnatural and fetid breath," Thucydides starts by saying.

But that was just the beginning - sneezing and coughing were next, then diarrhoea, vomiting and violent spasms.

Next came livid skin, covered in pustules and ulcers, and a burning, unquenchable thirst.