The plague killed a third of Europe’s population in the Middle Ages – but scientist and governments fear it could return.
It comes after research papers were found hidden at Mosul University after the fall of ISIS detailing experimentation using chemical weapons on human beings.
No evidence has been found so far of an advanced biological weapons programme.
But with ISIS imploding in Iraq and Syria it is feared the death cult could step-up any clandestine development and wreak revenge on the West.
World Health Organisation researchers estimated releasing a 50 kg aerosol cloud of plague bacteria over a city the size of London and its surrounding areas could cause at least 300,000 to become infected with 72,000 perishing from the nightmarish disease.
Meanwhile the Centers for Disease Control and Prevention in the US believe plague is a major concern along with anthrax, smallpox, and viral fevers like Ebola and Marburg.