The Black Death - Modern Nightmare?

Male Xenopsylla cheopis (oriental rat flea) engorged with blood. This flea is the primary vector of bubonic plague in most large plague epidemics in Asia, Africa, and South America. Both male and female fleas can transmit the infection. (It is important to realise though that Bubonic Plague is different from the Black Death which was a Haemorrhagic Plague (so named because extensive haemorraging is an important symptom))

We see that the total time corresponds exactly with the quarantine period established in the 14th century.

Here are the fingerprints of the most-wanted criminal, left behind when it disappeared 300 years ago. These are the characteristics of no known disease – this is completely new to medical science. Many people have looked at the plagues, but we are seeing what nobody has seen before.

Furthermore, we have discovered its secret weapon. The reason why the plague was able to hop over long distances (sometimes over 300 km) was because an incubation period of 32 days was sufficiently long, even in the days of primitive transport, to allow an infected person to travel widely. Often he was a trader, moving along the international trade routes of Europe. Once we have elucidated these basic characteristics of haemorrhagic plague, all the pieces of jigsaw fit together perfectly.
Because the infectious agent of the plagues is unknown to medical science, we conclude that it was a lethal virus that originally emerged from its animal host and then, critically, became directly infectious from one person to another.

Emerging Diseases