Historically, the plague has spread to other civilizations through warfare and trade. The massive death toll and speed with which the disease kills caused widespread panic and an irrational, violent response against specific groups of people. Relatively recently, the plague reached the U.S. in a similar way and was treated with much of the same fear and irrational paranoia. Thankfully improved scientific understanding of the disease has led to a realistic solution that is directed against another species rather than an ethnic group, however many countries still face this disease in their daily lives. Continuing progress in these countries will lead to an understanding of how the disease spreads and how to prevent it.
This was not the case in medieval Europe, when people did not understand where the plague came from or how it spread so rapidly. Trade between Europe and Asia and the transportation of furs and other goods (either as merchandise or loot) from areas affected by plague carried the disease to the western world. Animal vectors were also an important factor with rats moving to new areas through ships or infecting new cities during war (as in the siege of Caffa). However, the rats themselves did not carry the plague; it was the fleas which fed on the rats that brought the Black Death to Europe. Combined with poor sanitation and an ignorance of how diseases spread (disease was believed to be caused by “bad air” called misamas) the plague found a very susceptible population with weak immune defenses due to poor nutrition. Not only did the Europeans misunderstand the disease on a fundamental level, but the practice of taking care of the sick infected more people.
This virulent disease caused widespread fear and paranoia in the European population. While some of their responses seemed rational (e.g. quarantining the infected in lazarettos), they also blamed the Jewish people living in Europe at the time. After persecuting the Jews and eliciting false confessions through torture, Jews were burned at the stake by radical religious groups that believed the plague represented God’s displeasure at the Jew’s very existence. However, not everyone was so convinced that the plague was a divine scourge. Whereas some people took to extreme masochistic practices (called the flagellates), others began to question the veracity of the Catholic Church. This challenge to the Church’s authority was compounded by the Pope’s seclusion and the refusal of local priests to perform last rites on the dead; the common people were very much on their own.
After the Black Death had run its course, the survivors actually enjoyed a certain degree of benefits: studying the effects of the plague advanced medical science in a realistic direction, the demand for labor increased due to sudden decrease in population, there was a surplus of food and other resources, and medieval hierarchies collapsed. Now scientists understood that there was much about the natural world that they didn’t know, and the Bible did not provide the answer to all of the dangers that they could face.
Over the next few centuries, science and technology greatly improved, but did not quite prepare the world for another plague epidemic. This disease re-emerged in the late 19th century and while people had a better understanding of the nature of diseases this did not prevent paranoia from once again causing a number of irrational responses. Ineffective methods of control spawned from paranoia were once again put into place such as isolating the Chinese, blaming the Jews, and burning houses of the infected. In Hawaii, for example, buildings and homes in Chinatown were burned, leaving 4,000 people without homes. When the disease reached San Francisco, racially motivated quarantines and travel restrictions were used. Eventually, it was discovered in cities like Philadelphia that destroying the rat population prevented the spread of plague. Now that the specific organisms which transmit plague are known, the destruction of rats is common practice and has seen great success in the US while the infected are treated with antibiotics if they are diagnosed in time.
Plague is now endemic in the US and lives mostly in rodent populations. Occasionally, a large number of these rodents will die and their fleas will carry plague to other species (this is when humans have the greatest danger of becoming infected). The social norm of living in close contact with animals also puts humans at risk. Cats are particularly dangerous in that they have spread pneumonic plague to humans. Ironically, after all of the advances in medical science and our understanding of disease we still commit some of the same mistakes as our ancestors (e.g. taking care of the sick without protection and having viewing/other ceremonies with the dead). This can turn a single, isolated case into an epidemic, especially in countries that are less able to combat the plague.
Madagascar is an example of a country that is not as fortunate to both understand the causes of the disease and have the ability to prevent it. Since 2010, Madagascar has been the home of over half of the worldwide cases of plague with a high percentage of pneumonic plague (the most virulent form of the disease). After 2009, political upheaval and cutting of foreign aid decreased the standards of living for much of the country, and an increase in plague soon followed. The people of Madagascar also regularly dig up corpses and consult them for advice, going so far as to steal the bodies of the infected from hospitals. Many of the people live with animals or in slums with rats and spend a lot of time digging through dumps in close contact with rodents and other dead animals. Additionally, since the disease is known there is a stigma with having it which leads to people hiding their symptoms instead of seeking treatment. Hopefully, as these other countries progress into the 21st century their ability to treat and prevent plague will progress as well.