The Black Death

The Black Death was the most horrible pandemics in human history,peaking in Europe between 1348 and 1350, and killing between 75 million and 200 million people.
The Black Death is thought to have started in China or Central Asia.The plague then travelled along the Silk Road (trade route) and reached the Crimea by 1346.From there it was probably carried by Oriental rat fleas living on the black rat that were regular passenger on merchant ships.The Black Death had a drastic effect on Europe's population in the 14th century.It provoked a serious blow to the Catholic Church and resulted in widespread persecution of minorities such as Jews, foreigners, beggars, and lepers. 
causes:The importance of hygiene was recognised only in the XIX century; until then it was common that the streets were dirty, wich live animals of all sorts around and a lot of human parasites.
The Symptoms: of the plague are often varied or imprecise. The most commonly noted symptom was the appearance of buboes (or gavocciolos) in the groin, the neck and armpits, which causes pus and bleed when they open.




-The Plague reocurred occasionally in Europe  until the 19th century:

Italian Plague (1629-1631)
The Great Plague of Seville(1647-1652)
The Great Plague of London(1665-1666)
The Great Plague of Vienna(1679)
The Great Plague of Marseille (1720-1722)
The Great Plague of 1738,which hit Eastern Europe
The Russian Plague (1770-1772)

-The Black Death is estimated to have killed 30-60 percent of Europe's population.
-It took 150 years for Europe's population to recover.

Fuente de información: http://en.wikipedia.org/wiki/Black_Death