Yersinia pestis

Like no other disease, the plague personifies death. Among the most deadly infections of mankind's history, the “Black Death” stands in people's memory and fantast as a biblic synonym of malediction, altering the economy, demography, social life and possibly genetic background of the human populations that it devastated. Yet, it had slowly been considered as a disease of ancient times, wiped away by the progresses of medicine, and thus put aside as a bad memory. The plague however has never disappeared, for this disease can remain for decades in its animal reservoir before suddenly and brutally reappearing among humans. Since the begining of the nineties, it has even been included in the list of re-emerging diseases. The plague can also spread out of its known endemic foci, either with plague patients travelling during the incubation phase, or in imported goods containing infected rats or fleas and coming from endemic zones. Finally, a deliberate and evil-disposed introduction of the plague bacillus is also possible, as Yersinia pestis is among the bacteria considered as a first choice biologic weapon for terrorist use.