Europe, during the 1300s, was devastated by a plague pandemic which is famously known as Black Death. Many believed the disease to be a heavenly curse that horribly killed everyone. The disease mostly spread from fleas that traveled on rats. The unsanitary situation of medieval Europe helped spread the disease at a rocket speed.
The black death had an incubation period of 2-8 days in which the patient experienced multiple symptoms such as fever, chills, headache, swollen lymph nodes, and abdominal pain. All of it was a result of a flea bite that infected one’s body.
Analyzing the DNA of those century old skeletons, scientists discovered mutations that helped the Europeans survive the deadly disease. Data reveals almost 200 million people lost their lives during this pandemic outbreak. The death rate was so high that there was no space to bury the dead bodies.
The Medieval people who survived the black death shaped human evolution in some ways that make us prone to certain diseases today. The survivors had passed those mutations to their children.
Hendrik Poinar, an anthropology professor at McMaster, says “It’s huge we see a 10% shift over two to three generations, it’s the strongest selection event in humans to date.”
On Wednesday, Journal Nature published a report by Professor Luis Barreiro and it says, “Our genome today is a reflection of our whole evolutionary history” “So those scars from the past still impact our susceptibility to disease today, in a quite remarkable way.” Barreiro and his colleagues had examined the ancient DNA samples and bones of those 200 skeletons who died over a hundred years that stretched before and after the Black Death. They found what helped them protect themselves against the pandemic but led to autoimmune diseases later on; like rheumatoid arthritis, lupus, and Crohn’s disease.
Hendrik Poinar states “A hyperactive immune system may have been great in the past but in the environment today it might not be as helpful.”
After the Covid 19 pandemic that impacted the whole world, it gave birth to one important question, ‘Will Covid have an impact on human evolution?’.
Barreiro disagrees since the death rate is lower than the Bubonic plague and most of the people who died already had children.
However, he believes more pandemics will follow us in future and that can be dangerous.
“It’s not going to stop. It’s going to keep going for sure.”
So if you think we have left this plague in the past you’d be wrong. From 2010-2015 a total of 3,248 bubonic plague cases were reported and it resulted in 584 deaths. Peru, Congo, and Madagascar were the most affected places of all.