For most, the word “plague” creates horrible images in the mind of people dropping dead in European villages during the 1300s.
But the plague has been around for much longer than that. And the scary part is – it is still here.
As we often say, those who don’t learn from the past are sure to repeat it.
So, let’s talk about the past.
There are three forms of plague are they are all caused by the same bacteria. Bubonic plague develops in the lymph nodes. Pneumonic plague develops in the lungs. The third type, septicemic plague, is the rarest.
These diseases caused the Black Death. The Black Death killed at least a third of the European population in the mid-1300s.
However, that was not the first time the plague killed.
Danish researchers discovered new evidence that the bacterium responsible for the plague infected people thousands of years earlier.
And they discovered it by accident.
They were investigating remains of Bronze Age human beings when they found something unexpected.
Within the fossilized teeth, the researchers found the bacterium that causes Bubonic Plague. It proves the plague was around 4,800 years ago.
However, the bacterium that caused the Black Death was not nearly as aggressive during the Bronze Age. That is the opinion of Simon Rasmussen of Technical University in Denmark.
He helped examine more than 100 fossilized teeth. Only seven teeth had evidence of the plague bacterium Y. pestis. These teeth came from remains dating between 2,900 and 4,800 years ago. This suggests that back then, the bacterium did not spread as easily as it did later.
Infected fleas now pass the disease to humans. But genetic evidence proves that the plague did not stowaway, or catch a ride, on the insects during the Bronze Age.
Mr. Rasmussen explains.
"The plague in the Bronze Age is missing the gene that makes it able to survive inside the flea. So, what we think is the plague could not actually be transmitted by fleas back then."
The findings from the study were reported in the journal Cell.
How disease affects civilizations
In another research paper, the same researchers demonstrated a link between this genetic evidence and the history of some world civilizations.
Their paper caused quite a stir, meaning it fueled some interesting discussions. The paper suggests that the plague may have been partly to blame for widespread disease in ancient civilizations. The researchers said the disease could have led to the collapse of Classical Greece and weakened the ancient Roman army.
The researcher Simon Rasmussen says disease may also have led to a number of ancient mass migrations, or people moving from one place to another. Of course, people would want to flee from disease. Again, here is Mr. Rasumssen.
"Still today and also in the Middle Ages, if there were some kind of disease outbreak, then often people would try to flee from it."
But he says the migrants brought the disease with them when they settled new areas.
Plague still among us
If you think that cases of the plague are only part of the history of world health – think again. They are rare, but outbreaks do happen.
The plague struck in India in 1994. At the time, Indian health officials reported nearly 700 cases to the World Health Organization.
There were several small outbreaks in 2014.
Four people in the United States were identified with pneumonic plague. Pneumonic plague is the only form of the disease that can be passed from person-to-person.
Also in 2014, a Chinese man died from the plague after chopping up a dead animal and feeding it to his dogs. No one else died, but Chinese health official quarantined the town where he lived until they were sure no one else had caught the plague.
The WHO website says there is a current outbreak of plague in Madagascar. The height of this outbreak was in November 2014. At that time, health officials there reported over 300 cases and almost 80 deaths.
If antibiotic treatment is given during the early stages of the disease, Mr. Rasmussen says, the plague is almost completely curable.
Words in This Story
fossil – n. preserved from a past geologic age : fossilize – v. to become changed into a fossil
transmit – v. to cause to be given to others, such as a virus or disease
gene – n. biology : a part of a cell that controls or influences the appearance, growth, etc., of a living thing (genomic, genetic
stowaway – n. someone who hides on a ship, airplane, etc., in order to travel without paying or being seen
outbreak – n. a sudden start or increase of fighting or disease
flee – v. to run away from danger : to run away from (a place)
migrant – n. a person who goes from one place to another especially
rare – adj. seldom occurring or found : uncommon
quarantine – v./n. the period of time during which a person or animal that has a disease or that might have a disease is kept away from others to prevent the disease from spreading