The Black Death is estimated to have killed 30% – 60% of Europe's population, reducing the world's population from an estimated 450 million to between 350 and 375 million in 1400. Fear and fanciful notions took possession of the living that almost all of them adopted the same policy to entirely avoid the sick and everything belonging to them.
The Black Death has been seen as having created a series of religious, social and economic upheavals, which had profound effects on the course of European history. In this suffering and misery of infested cities, the authority of human almost disappeared. The ministers and the executors of the laws were all dead or sick or shut up with their families, thus no duties were carried out.
Every man was able to do as he pleased and many did exactly that. A multitude of corpses was brought to the churches every day and almost every hour. There was not enough consecrated ground to give proper burials, especially since the people wanted to bury each person in the family grave, according to the old custom.
Eventually the people were forced to dig huge trenches and conduct mass burials. It took 150 years for Europe's population to recover. The next few centuries were marked by several local outbreaks of lesser severity. The Great Plague of Seville (1647), the Great Plague of London (1665–1666), the Great Plague of Vienna (1679), and the Great Plague of Marseille (1720), were the last major outbreaks of the bubonic plague in Europe.
Recent cases of the plague
In the United States, the last urban plague epidemic occurred in Los Angeles in 1924-25. Since then, human plague in the United States has occurred as scattered cases in rural areas. An average is 10 to 15 persons per year. In North America, plague is found in certain animals and their fleas from the Pacific Coast to the Great Plains, and from southwestern Canada to Mexico. Human cases usualy occur in two regions: northern New Mexico, northern Arizona, and southern Colorado; and California, southern Oregon, and far western Nevada. Plague also exists in Africa, Asia, and South America.
The primary protection against the Black Plague is personal hygiene. Modern sewage systems and public health systems keep the plague to a minimum in the western countries, but because of the poor life conditions in other parts of the world a small risk still exists. The usual procedure in a case is patient isolation, retracement of his movements and the destruction of the rodent population responsible for the outbreak.